This adds the ability for the orchestrator to add a new bucket
into the config dict keyed 'orchestrator', which can be used to
notify the appliance of the specifics about the orchestrator currently
managing it. Initially this will be used to inform the appliance where
the metadata service is running, but in the future could be extended
to do more, specifically around coordination.
Change-Id: I4a4009f12ce025d3dc6577d27f877aeb8427b963
Partial-bug: #1524068
44610ac1cd