MB-8726: implemented upload of terse bucket infos to ep-engine

Change-Id: I8f0a3fea054d1b4a58cc93707e38dc3420fa523a
Reviewed-on: http://review.couchbase.org/29997
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>