JCBC-526: Add support for bucket management operations.

Change-Id: I70fb4b4018b2070854791c85dab6f31ce9af328a
Reviewed-on: http://review.couchbase.org/40838
Reviewed-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>