List federated projects and domains

Add calls for utilizing ``/OS-FEDERATION/projects`` and
``/OS-FEDERATION/domains``.

Change-Id: I670c1f284c1980e2258881caf51801ea66645c4a
Control identity plugin reauthentication

Identity plugins will by default re-authenticate themselves if they are
about to expire. This is generally correct however there are times where
this re-authentication doesn't make sense and we should be able to
prevent it.

Closes-Bug: #1352051
Change-Id: I66b50b1e650501e7f076139895473e8d1791ce27
Merge "Control identity plugin reauthentication"
Merge "List federated projects and domains"