docs: better docs, mv doxygen to sphinx

This patch refactors the VPP sphinx docs
in order to make it easier to consume
for external readers as well as VPP developers.

It also makes sphinx the single source
of documentation, which simplifies maintenance
and operation.

Most important updates are:

- reformat the existing documentation as rst
- split RELEASE.md and move it into separate rst files
- remove section 'events'
- remove section 'archive'
- remove section 'related projects'
- remove section 'feature by release'
- remove section 'Various links'
- make (Configuration reference, CLI docs,
  developer docs) top level items in the list
- move 'Use Cases' as part of 'About VPP'
- move 'Troubleshooting' as part of 'Getting Started'
- move test framework docs into 'Developer Documentation'
- add a 'Contributing' section for gerrit,
  docs and other contributer related infos
- deprecate doxygen and test-docs targets
- redirect the "make doxygen" target to "make docs"

Type: refactor

Change-Id: I552a5645d5b7964d547f99b1336e2ac24e7c209f
Signed-off-by: Nathan Skrzypczak <nathan.skrzypczak@gmail.com>
Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com>
diff --git a/docs/gettingstarted/progressivevpp/index.rst b/docs/gettingstarted/progressivevpp/index.rst
index ab257f2..7d1a2e2 100644
--- a/docs/gettingstarted/progressivevpp/index.rst
+++ b/docs/gettingstarted/progressivevpp/index.rst
@@ -14,8 +14,6 @@
 
     This is **not** intended to be a 'How to Run in a Production Environment' set of instructions.
 
-For more information on using VPP with Virtual Box/Vagrant, please refer to :ref:`vppvagrant`
-
 .. toctree::
 
    settingupenvironment.rst
diff --git a/docs/gettingstarted/progressivevpp/interface.rst b/docs/gettingstarted/progressivevpp/interface.rst
index 112eaa9..7e35ca8 100644
--- a/docs/gettingstarted/progressivevpp/interface.rst
+++ b/docs/gettingstarted/progressivevpp/interface.rst
@@ -41,7 +41,7 @@
 
 The initial state here is presumed to be the final state from the previous sections
 of the tutorial.
- 
+
 Create veth interfaces on host
 -------------------------------
 
@@ -104,7 +104,7 @@
      __/ __/ _ \  (_)__    | | / / _ \/ _ \
      _/ _// // / / / _ \   | |/ / ___/ ___/
      /_/ /____(_)_/\___/   |___/_/  /_/
-    
+
     vpp#
 
 Create a host interface attached to **vpp1out**.
diff --git a/docs/gettingstarted/progressivevpp/routing.rst b/docs/gettingstarted/progressivevpp/routing.rst
index c9586c1..38841b7 100644
--- a/docs/gettingstarted/progressivevpp/routing.rst
+++ b/docs/gettingstarted/progressivevpp/routing.rst
@@ -50,10 +50,10 @@
 
    $ sudo ip route add 10.10.2.0/24 via 10.10.1.2
    $ ip route
-   default via 10.0.2.2 dev enp0s3 
-   10.0.2.0/24 dev enp0s3  proto kernel  scope link  src 10.0.2.15 
-   10.10.1.0/24 dev vpp1host  proto kernel  scope link  src 10.10.1.1 
-   10.10.2.0/24 via 10.10.1.2 dev vpp1host 
+   default via 10.0.2.2 dev enp0s3
+   10.0.2.0/24 dev enp0s3  proto kernel  scope link  src 10.0.2.15
+   10.10.1.0/24 dev vpp1host  proto kernel  scope link  src 10.10.1.1
+   10.10.2.0/24 via 10.10.1.2 dev vpp1host
 
 Setup return route on vpp2
 ---------------------------
diff --git a/docs/gettingstarted/progressivevpp/runningvpp.rst b/docs/gettingstarted/progressivevpp/runningvpp.rst
index 19d2f4e..c24d104 100644
--- a/docs/gettingstarted/progressivevpp/runningvpp.rst
+++ b/docs/gettingstarted/progressivevpp/runningvpp.rst
@@ -50,7 +50,7 @@
     __/ __/ _ \  (_)__    | | / / _ \/ _ \
     _/ _// // / / / _ \   | |/ / ___/ ___/
     /_/ /____(_)_/\___/   |___/_/  /_/
-   
+
    vpp# show version
    vpp v18.07-release built by root on c469eba2a593 at Mon Jul 30 23:27:03 UTC 2018
    vpp#
diff --git a/docs/gettingstarted/progressivevpp/settingupenvironment.rst b/docs/gettingstarted/progressivevpp/settingupenvironment.rst
index c012f69..8c67c79 100644
--- a/docs/gettingstarted/progressivevpp/settingupenvironment.rst
+++ b/docs/gettingstarted/progressivevpp/settingupenvironment.rst
@@ -11,8 +11,7 @@
 Install Virtual Box and Vagrant
 -------------------------------
 
-You will need to install Virtual Box and Vagrant. If you have not installed Virtual Box or Vagrant please
-refer to :ref:`installingVboxVagrant` to install Virtual Box and Vagrant.
+You will need to install Virtual Box and Vagrant.
 
 Create a Vagrant Directory
 ---------------------------
@@ -30,17 +29,17 @@
 
     # -*- mode: ruby -*-
     # vi: set ft=ruby :
-    
+
     Vagrant.configure(2) do |config|
-    
+
       config.vm.box = "bento/ubuntu-18.04"
       config.vm.box_check_update = false
-    
+
       vmcpu=(ENV['VPP_VAGRANT_VMCPU'] || 2)
       vmram=(ENV['VPP_VAGRANT_VMRAM'] || 4096)
-    
+
       config.ssh.forward_agent = true
-    
+
       config.vm.provider "virtualbox" do |vb|
           vb.customize ["modifyvm", :id, "--ioapic", "on"]
           vb.memory = "#{vmram}"
@@ -129,7 +128,7 @@
 
 We will create some startup files for the use of this tutorial. Typically you will
 modify the startup.conf file found in /etc/vpp/startup.conf. For more information
-on this file refer to :ref:`startup`.
+on this file refer to :ref:`configuration_reference`.
 
 When running multiple VPP instances, each instance needs to have
 specified a 'name' or 'prefix'. In the example below, the 'name' or 'prefix'
diff --git a/docs/gettingstarted/progressivevpp/switching.rst b/docs/gettingstarted/progressivevpp/switching.rst
index a28e860..7ee5598 100644
--- a/docs/gettingstarted/progressivevpp/switching.rst
+++ b/docs/gettingstarted/progressivevpp/switching.rst
@@ -80,8 +80,8 @@
 .. code-block:: console
 
    vpp# show bridge-domain
-    ID   Index   Learning   U-Forwrd   UU-Flood   Flooding   ARP-Term     BVI-Intf   
-    0      0        off        off        off        off        off        local0    
+    ID   Index   Learning   U-Forwrd   UU-Flood   Flooding   ARP-Term     BVI-Intf
+    0      0        off        off        off        off        off        local0
 
 In the example above, there is bridge domain ID '0' already. Even though
 sometimes we might get feedback as below:
@@ -175,15 +175,15 @@
 .. code-block:: console
 
     vpp# show l2fib verbose
-    Mac Address     BD Idx           Interface           Index  static  filter  bvi   Mac Age (min) 
-    de:ad:00:00:00:00    1            host-vpp1vpp2           2       0       0     0      disabled    
-    c2:f6:88:31:7b:8e    1            host-vpp1out            1       0       0     0      disabled    
+    Mac Address     BD Idx           Interface           Index  static  filter  bvi   Mac Age (min)
+    de:ad:00:00:00:00    1            host-vpp1vpp2           2       0       0     0      disabled
+    c2:f6:88:31:7b:8e    1            host-vpp1out            1       0       0     0      disabled
     2 l2fib entries
 
 .. code-block:: console
 
     vpp# show l2fib verbose
-    Mac Address     BD Idx           Interface           Index  static  filter  bvi   Mac Age (min) 
-    de:ad:00:00:00:00    1                loop0               2       1       0     1      disabled    
-    c2:f6:88:31:7b:8e    1            host-vpp2vpp1           1       0       0     0      disabled    
+    Mac Address     BD Idx           Interface           Index  static  filter  bvi   Mac Age (min)
+    de:ad:00:00:00:00    1                loop0               2       1       0     1      disabled
+    c2:f6:88:31:7b:8e    1            host-vpp2vpp1           1       0       0     0      disabled
     2 l2fib entries
diff --git a/docs/gettingstarted/progressivevpp/traces.rst b/docs/gettingstarted/progressivevpp/traces.rst
index a340858..d1dfad5 100644
--- a/docs/gettingstarted/progressivevpp/traces.rst
+++ b/docs/gettingstarted/progressivevpp/traces.rst
@@ -2,7 +2,7 @@
 
 .. toctree::
 
-Using the trace command 
+Using the trace command
 ========================
 
 Skills to be Learned
@@ -21,26 +21,26 @@
 
 Show trace buffer [max COUNT].
 
-.. code-block:: console 
+.. code-block:: console
 
   vpp# show trace
 
 Clear trace buffer and free memory.
 
-.. code-block:: console 
+.. code-block:: console
 
   vpp# clear trace
 
 filter trace output - include NODE COUNT | exclude NODE COUNT | none.
 
-.. code-block:: console 
+.. code-block:: console
 
   vpp# trace filter <include NODE COUNT | exclude NODE COUNT | none>
 
 Add Trace
 ----------
 
-.. code-block:: console 
+.. code-block:: console
 
   vpp# trace add af-packet-input 10
 
@@ -69,7 +69,7 @@
 Ping from Host to VPP
 ----------------------
 
-.. code-block:: console 
+.. code-block:: console
 
   vpp# q
   $ ping -c 1 10.10.1.2
@@ -80,10 +80,10 @@
   1 packets transmitted, 1 received, 0% packet loss, time 0ms
   rtt min/avg/max/mdev = 0.283/0.283/0.283/0.000 ms
 
-Examine Trace of ping from host to VPP 
+Examine Trace of ping from host to VPP
 ----------------------------------------
 
-.. code-block:: console 
+.. code-block:: console
 
   $ sudo vppctl -s /run/vpp/cli-vpp1.sock
   vpp# show trace
@@ -144,14 +144,14 @@
 Clear trace buffer
 -------------------
 
-.. code-block:: console 
+.. code-block:: console
 
   vpp# clear trace
 
-Ping from VPP to Host 
+Ping from VPP to Host
 -----------------------
 
-.. code-block:: console 
+.. code-block:: console
 
   vpp# ping 10.10.1.1
   64 bytes from 10.10.1.1: icmp_seq=1 ttl=64 time=.0789 ms
@@ -167,7 +167,7 @@
 
 The output will demonstrate FD.io VPP's trace of ping for all packets.
 
-.. code-block:: console 
+.. code-block:: console
 
   vpp# show trace
   ------------------- Start of thread 0 vpp_main -------------------
@@ -465,16 +465,16 @@
 Examine ARP table (neighbors)
 -----------------------------
 
-.. code-block:: console 
+.. code-block:: console
 
   vpp# show ip neighbors
   Time           IP4       Flags      Ethernet              Interface
-  1101.5636    10.10.1.1      D    e2:0f:1e:59:ec:f7 host-vpp1out        
+  1101.5636    10.10.1.1      D    e2:0f:1e:59:ec:f7 host-vpp1out
 
 Examine routing tables
 -----------------------
 
-.. code-block:: console 
+.. code-block:: console
 
   vpp# show ip fib
     ipv4-VRF:0, fib_index:0, flow hash:[src dst sport dport proto ] locks:[src:plugin-hi:2, src:adjacency:1, src:default-route:1, ]
diff --git a/docs/gettingstarted/progressivevpp/twovppinstances.rst b/docs/gettingstarted/progressivevpp/twovppinstances.rst
index c6a7420..eadd4e6 100644
--- a/docs/gettingstarted/progressivevpp/twovppinstances.rst
+++ b/docs/gettingstarted/progressivevpp/twovppinstances.rst
@@ -64,7 +64,7 @@
      __/ __/ _ \  (_)__    | | / / _ \/ _ \
      _/ _// // / / / _ \   | |/ / ___/ ___/
      /_/ /____(_)_/\___/   |___/_/  /_/
-    
+
     vpp# show version
     vpp v18.07-release built by root on c469eba2a593 at Mon Jul 30 23:27:03 UTC 2018
     vpp# quit
@@ -121,7 +121,7 @@
 
 .. code-block:: console
 
-    $ ping 10.10.2.2 
+    $ ping 10.10.2.2
 
 Ping 10.10.2.1 from vpp2