A Gluon ML2 Driver that wraps and subclasses original ML2 driver to support Proton ports and Neutron ports

This blueprints is for Developing a Gluon ML2 Driver (core plugin) such that:
- Gluon Wrapper ML2 Driver subclasses ML2 Driver
- If it is Proton port, sends to Proton
- Otherwise, goes to normal ML2 driver

Dummy network, subnets etc. object will be used by Gluon ML2 driver to satisfies Nova-Neutron relationship.

Backend SDN controllers will create network, subnets etc. in our desired way.

South Bound stays the same etcd to communicate via Shim Layers with SDN Controllers so that
- Gluon ML2 core plugin will connect with etcd to determine port ownership
- Contrail will use existing plugin/mechanism driver, which is at the same level as etcd.
- Contrail’s mechanism driver needs to work with Gluon ML2 Core Plugin

The steps of exploring Gluon ML2 Core Plugin are:
- Experiment with wrapping / sub-classing method
 * If successful, done
- If not successful, we try to fix ML2 by working with Neutron ML2 team
 * If successful, done
- If not successful, we will use Original Gluon Model, i.e. Nova-Gluon-Neutron
 * Customization for commercial deployment