mod_callcenter: Remove the concept of Caller for Members. Event Socket event…

mod_callcenter: Remove the concept of Caller for Members.  Event Socket event have been changed (CC-Caller.* to CC-Member.*)  Also CC-Caller-UUID is renamed to CC-Member-Session-UUID.
The reason for this is you could actually put people to be call in the queue.  So they are not caller per say.  But they are a member of a queue.