MB-7656 Add bitmap data structure and operations

Change-Id: Idabd34c8f56602fc3adca87021c75d2932756a46
Reviewed-on: http://review.couchbase.org/24287
Reviewed-by: Fulu Li <fulu@couchbase.com>
Tested-by: Fulu Li <fulu@couchbase.com>
Reviewed-by: Aaron Miller <apage43@ninjawhale.com>
Tested-by: Aaron Miller <apage43@ninjawhale.com>
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Filipe David Borba Manana <fdmanana@gmail.com>