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/conf.py b/docs/conf.py
index 09c4d9b..8a2aef5 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -16,6 +16,8 @@
 # import sys
 # sys.path.insert(0, os.path.abspath('.'))
 
+import subprocess
+
 # -- Project information -----------------------------------------------------
 
 project = u'The Vector Packet Processor'
@@ -23,9 +25,9 @@
 author = u'FD.io VPP Community'
 
 # The short X.Y version
-version = u'master'
+version = subprocess.run(["git", "describe"], stdout=subprocess.PIPE, text=True).stdout
 # The full version, including alpha/beta/rc tags
-release = u'20.01'
+release = subprocess.run(["git", "describe", "--long"], stdout=subprocess.PIPE, text=True).stdout
 
 
 # -- General configuration ---------------------------------------------------
@@ -44,6 +46,10 @@
     'sphinxcontrib.spelling']
 
 spelling_word_list_filename = 'spelling_wordlist.txt'
+
+# do not spell check those files
+spelling_exclude_patterns = ['aboutvpp/releasenotes/*']
+
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']
 
@@ -68,7 +74,7 @@
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
 # This pattern also affects html_static_path and html_extra_path .
-exclude_patterns = [u'_build', 'Thumbs.db', '.DS_Store']
+exclude_patterns = ['Thumbs.db', '.DS_Store', '_scripts', 'venv', '_generated']
 
 # The name of the Pygments (syntax highlighting) style to use.
 pygments_style = 'default'