Identity Fixtures - Role Tests Parity

1. Added extensions-api client.
2. Added extensions-api configuration parameters.
3. Fixed a code reviewer comment.
4. Added tenants-api configuration parameters.
5. Fixed reviewer comments - remove useless init method in fixtures.
6. Refactored fixtures.
7. Fixed reviewer comment - renamed deserialize_format to serialize_format.
8. Renamed test_repo to cloudroast.

Change-Id: I9b48e3e2627b50535c1b1b145e68de5413fb155a
Merge "Identity Fixtures - Role Tests Parity"