poc: Introduce Proof of Concepts (Package building)

poc: Introduce Proof of Concepts (Package building)

This patch sets up foundations for Proof of Concepts that
simply materialize documentation into Ansible instructions
executed in virtualized Vagrant environment.

This Proof of Concept allows to easily build:
1. *.deb packages on Ubuntu 16.04; AND
2. *.rpm packages on CentOS 7.4.
It also sets up DEB and RPM repository over HTTP that can
be used to pull these openvswitch packages with apt-get
or yum from another host.

This particular Proof of Concept is intended to address
following use-cases:
1. for new OVS users to see how debian and rpm packages are
   built;
2. for developers to easily check for packaging build
   regressions;
3. for developers to easily share their sandbox builds
   into QE setups (opposed to manually copying binaries);
4. for developers to add other Proof of Concepts
   that possibly may require full end-to-end integration
   with other thirdparty projects (e.g. DPI, libvirt, IPsec)
   and need Open vSwitch packages.

Tested-by: Greg Rose <gvrose8192@gmail.com>
Reviewed-by: Greg Rose <gvrose8192@gmail.com>
Signed-off-by: Ansis Atteka <aatteka@ovn.org>