MB-5641 Limit bucket name length to 100 chars

Change-Id: Ic5cf7733d4af5451247a950ec871fb6b13ce3941
Reviewed-on: http://review.couchbase.org/27747
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>