CP-7916: Reinstate XenAPI WLB code back

Signed-off-by: Phus Lu <phus.lu@citrix.com>
CP-8155: Code change for xapi and v6d in Creedence to make WLB as a licensed feature

Signed-off-by: Phus Lu <phus.lu@citrix.com>
CA-80791:WLB | perhaps vm-retrieve-wlb-recommendations should return host-uuids, to enable user to differentiate between same-named hosts

Signed-off-by: Cheng Zhang <cheng.zhang@citrix.com>
Merge commit '9edddce5194f70956ea978e11000d48806174f03'
CP-8155: Code change for xapi and v6d in Creedence to make WLB as a licensed feature

Signed-off-by: Phus Lu <phus.lu@citrix.com>