Confirm managed call when there are ongoing self-managed calls.

When the user places a managed call while there are ongoing self-managed
calls, the system will now display a dialog giving the user the option of
NOT placing the managed call, or placing the managed call and disconnecting
the ongoing self-managed call(s).

This is done by stopping the outgoing call during startOutgoingCall and
bringing up a dialog to confirm whether the user wants to place the call.
If they chose to place the call, ongoing self-mgds calls are disconnected,
the call is added, and the NewutgoingCallBroadcast is sent as usual.

If the user chooses not to start the call, the call is cancelled.

Test: Manual
Bug: 37828805
Merged-In: I8539b0601cf5f324d2fb204485ee0d9bbf03426d
Change-Id: I8539b0601cf5f324d2fb204485ee0d9bbf03426d
8 files changed