PLUMgrid quantum plugin

PLUMgrid plugin supports Quantum Core V2 APIs over an infrastructure running
PLUMgrid Network Virtualization Platform.
The plugin will interact directly with the Hypervisor layer to provide all the
networking functionality requested by Quantum APIs.
It will be based on a controller-mode implementation were all resources state
will be controlled and handled by the plugin.

Implements: blueprint plumgrid-quantum-plugin
Change-Id: I6bc8d32b83982e10f661913e85494468cf10e0e2
Merge "PLUMgrid quantum plugin"