Add field to store who is initiating the call

Insert userhandle of user that initiate the call before forwarding
the intent to primary user.

Previous ACTION_CALL flow:
Fire ACTION_SEND (managed user) ->
UserCallActivity in Telecom (parent user) ->
PrimaryCallReceiver (parent user)

Current ACTION_CALL flow:
Fire ACTION_SEND (managed user) ->
UserCallActivity in Telecom (managed user) ->
PrimaryCallReceiver (parent user)

The field can be used for:
1. Filter phone accounts for outgoing call
2. Insert call log based on who initiates the call
3. Pass the field to in-call UI which may uses it to indicate it is a work
   call.


Change-Id: I78611a4394f00ce0655c37d52b7b456f213ec802