Integrate MMTel APIs into the framework

1) Integrates the new ImsService APIs into ImsManager.

2) Removes all Compat layers (ImsServiceProxy) and
moves all relevant functionality into
MmTelFeatureConnection. Also tries to encapsulate more
of the MmTel specific functionality in this class.

3) Compat method for ImsConnectionStateListener that
converts old method of updating MMTel capabilites
to the new method.

Bug: 63987047
Test: Telephony Test ImsService App
Change-Id: Ic30429bed05191f00a8e4bc1d2b63f125d4e7524