Add ImsStateCallbackController

registerImsStateCallback and unregisterImsStateCallback are
added to ImsMmTelManager, ImsRcsManager, and SipDelegateManager.
Those are used to receive updates about the connection state
of the underlying ImsService.

ImsStateCallbackController notifies the state of the ImsService
via the registered IImsStateCallback callback interface.

Bug: 178016400
Test: atest ImsStateCallbackControllerTest
Change-Id: I336761a7174bf35d72b6bd0e3040db58fef54daa
4 files changed