feat(sql/driver): expose ControlDriver, more config

This patch adds two features to our current sqlalchemy driver:

- option to configure connection URI for driver
- Skeleton of ControlDriver written

With the ControlDriver, the expected methods were stubbed out.

Small fix: all controller methods not yet implemented now raise
NotImplementedError.

Change-Id: I1cd4a4d75cbbee7f0ff574c5be4d11660359ab7e
Partially-Implements: blueprint: sql-storage-driver
Merge "feat(sql/driver): expose ControlDriver, more config"