Gimbal v2 manager messages missing

The vast majority of messages from the Gimbal v2 protocol are missing from `common.xml` (e.g. GIMBAL_MANAGER_INFORMATION - 280, GIMBAL_MANAGER_STATUS - 281 etc). 

Is this omission an intentional decision? Upstream has had these messages for a while now. It is technically still marked as WIP in the documentation, but other WIP messages - including the gimbal v2 device messages - are included.
