First phase of migration to using composites for Compute tests

* Replaced all instances of config/client generation with properties
  from the compute composite. The next phase will try to collapse
  the fixtures completely
* Fixed variable references where necessary
* Modified authorization test to allow it to generate the necessary clients

Change-Id: I7cdd4daa535d8fd71e0bdf7ec9116465bece1a2d
First phase of converting Ironic tests to use composites

* Modified Ironic fixture to use composite to get instances
  of individual components

Change-Id: Ic6d1fd501b87b980a92d4e162eff8b5252216543
Merge "First phase of migration to using composites for Compute tests"
Merge "First phase of converting Ironic tests to use composites"