JCBC-522: Add bucket info API.

Change-Id: Ifb97bd0f5cde95ba68a1358749a2884b4d4bd694
Reviewed-on: http://review.couchbase.org/40823
Reviewed-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>