Refactor integrated tests to support V2 and V3 API testing

Refactors the integrated test classes so they can be used
for both V2 and V3 API testing. No actual V3 testing is
added in this changeset.

Partially implements blueprint v3-api-unittests
Partially implements blueprint v3-api-specification

Change-Id: Ic7d7b513c3bc19ac1962c0a8489b55e9685fb7c0
Merge "Refactor integrated tests to support V2 and V3 API testing"