Integrate Registration APIs

1) Pipe ImsRegistration interface through ImsResolver
so that ImsManager can access the ImsService's
Registration APIs.

2) Tear down ImsManager when the ImsService becomes
unavailable and recreate it with the new ImsService.

3) Update namespaces.

Bug: 63987047
Test: Manual, Telephony unit tests
Change-Id: I1e07e15bc8effc06a4687183f0e67f4e253656ab