Configure the Ceph mgr daemon completely from the operator a la the
recent changes to the Ceph mon operator.

The pod spec for the mgr changed quite a bit, and instead of updating
the unit tests of questionable use, some additional unit test tools
applicable to any Ceph daemon have been added and used with the mgr. The
mgrs unit tests should now be more useful and get in the way of devs
less, and they can be used by other daemons later.
Signed-off-by: Blaine Gardner <blaine.gardner@suse.com>