CouchbaseScopeGroup

        CouchbaseScopeGroup represents a logical unit of data storage that sits between buckets and
collections e.g. a bucket may contain multiple scopes, and a scope may contain multiple
collections.  At present, scopes are not nested, so provide only a single level of
abstraction.  Scopes provide a coarser grained basis for role-based access control (RBAC)
and cross-datacenter replication (XDCR) than collections, but finer that buckets.
In order to be considered by the Operator, a scope must be referenced by either a
`CouchbaseBucket` or `CouchbaseEphemeralBucket` resource.
Unlike `CouchbaseScope` resources, scope groups represents multiple scopes, with the same
common set of collections, to be expressed as a single resource, minimizing required
configuration and Kubernetes API traffic.  It also forms the basis of Couchbase RBAC
security boundaries.