In the form of mon, mgr, mds, and rgw, convert the rbd-mirror to be
configured completely from the operator. This is a straightforward
conversion with one functional addition: the rbd-mirror daemon stores
*no* data and has no default data dir, so the concept of a `Dataless`
daemon is here introduced.
Signed-off-by: Blaine Gardner <blaine.gardner@suse.com>