Initial creation of db models, modules, and tests

Added sqlalchemy models mirroring initial migration
Added engine and session methods based off oslo.db
Added base db test based off of oslo.db
Added model tests
Added data models
Added data model tests
Added migration for one to many load balancer to amphora
Added migration for name and URL size changes
Added smarter comparison method for data models

Implements: blueprint initial-db-models

Change-Id: I8421093f0952d5e3ef287bfd4979cc5a83af6c09
Merge "Initial creation of db models, modules, and tests"