Port multinic extension to v3 API Part 2
Port multinic extension to v3 API Part 2

Ports the multinic extension and the corresponding unittests to
the v3 framework.

Partially implements blueprint nova-v3-api

Change-Id: I5688b66734daa05eb92501f16a8413a194c5fa30

n0ano/gantt,n0ano/gantt