Firewall as a Service (FWaaS) APIs and DB Model

Implements: blueprint quantum-fwaas

blueprint: quantum-fwaas-plugin

This is the first iteration of the FWaaS implementation and
is geared towards implementing the model that will be
required to at least address the reference implementation.

This iteration will not include implementation of the following
features:
* grouping or dynamic objects
* application/service objects

Change-Id: I57a62d6e9d3f1e6c4dd44cd5c745710a3d9e488e
Merge "Firewall as a Service (FWaaS) APIs and DB Model"