CBQE-1796 add rest call to collect vbucketmap,
server list and number replica from given bucket

Change-Id: Ifcf2f19ce3a23bf8da6bc16c8b74646a599fd1ea
Reviewed-on: http://review.couchbase.org/31258
Tested-by: Thuan Nguyen <soccon@gmail.com>
Reviewed-by: Aruna Piravi <aruna@couchbase.com>