Adding Auth, Compute and Blockstorage composites

 * Composites aggregate the various clients, behaviors and configs
   for service subpackages into standalone classes for use in
   tests, data generators, fixtures, etc.
 * Cleans up import clutter by providing a single import for the
   entirety of a service's functionality.
 * Self-authing composites pull the data they need (as defined
   by their configs) from the access data usng the AuthProvider
 * Memoized auth method means that a composite will only ever
   auth once no matter how many times it's instantiated, so logs
   aren't cluttered with multiple, superfluous auth attempts.

Change-Id: I347048f3f5d2f7153181df978f0afa3e65a4f145
Added StatusProgressionVerifer class to common/behaviors.py

 * Added common/behaviors.py
 * Provides a way to verify that an action on a resource
   progresses through states as expected.

Change-Id: Ie662cb2a611cc447161d811c30aacb81c6a55872
Merge "Adding Auth, Compute and Blockstorage composites"
Merge "Added StatusProgressionVerifer class to common/behaviors.py"