vpp_config: Rework for Python2/3 compatibility.

On ubuntu:
   $cd <basedir>/extras/vpp_config
   $./scripts/clean.sh
   $./scripts/cp-data.sh
   $sudo apt-get install python3-pip python3-setuptools
   $python3 -m pip install .
   $vpp-config

Changes:
   * Convert to print() function.
   * raw_input changes.
   * floor division changes.
   * replace vpp-config.py with a setuptools 'vpp-config' entry_point.
   * replace netaddr with ipaddress from the standard library and backport.
   * .decode() subprocess.Popen's stdout because in python3 they are bytes.

Change-Id: Id98894ee54e0c31a0ba0304134b159caef415705
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
diff --git a/extras/vpp_config/scripts/dpdk-devbind.py b/extras/vpp_config/scripts/dpdk-devbind.py
index f1d374d..b65677d 100755
--- a/extras/vpp_config/scripts/dpdk-devbind.py
+++ b/extras/vpp_config/scripts/dpdk-devbind.py
@@ -1,4 +1,4 @@
-#! /usr/bin/python
+#! /usr/bin/env python
 #
 #   BSD LICENSE
 #
@@ -647,5 +647,6 @@
     get_crypto_details()
     do_arg_actions()
 
+
 if __name__ == "__main__":
     main()