Rename core/juju to core/instance
Clean up terminology to better reflect Juju

A Bundle is one of our service (mysql)
An instance is an instance of the bundle.  It may comprise multiple Juju services
More refactoring
Filter the tenant when we first receive it
New names for some fields in the RPC call
Parse the unit out of the service id
Huddle references a Service, which has a BundleStore
Get overall Status for an Juju service, by combining unit statuses
Able to fetch status of all the Juju services that make up the bundle