This is the first part of the more comprehensive split of
assignments, which rationalizes both the backend and controllers.
In order to make this change easier for reviewers, it is divided
into a number of smaller patches.
Follow-on patches will:
- Fix incorrect doc strings for grant driver methods
- Update unit tests to call the new role manager
- Update the assignment controller to call the role manager
- Refactor assignment manager and driver methods to logically
separate project/domains from the actual assignments
- Split projects and domains into their own backend
- Split the controllers so they call the correct manager
- Update the tests to call the new correct manager
Partially implements: bp pluggable-assignments
Change-Id: I41fc23a049c26e514222a966c1847e183448be00
3408515e8c