reates base implementation of ImsService AIDLs

This change introduces "base classes" of the AIDL interfaces that are
implemented in vendor provided ImsServices. This allows for new APIs
to be added to the AIDL files, along with stub implementation of those
AIDLs in the base classes. By extending from the base class, older
implementations of the AIDL interfaces will not need to be updated
when the interface changes.

This change also moves some of the com.android.ims classes from
frameworks/opt/net/ims to frameworks/base. Any class that will be
used in the new unbundled ImsService system will need to be in
the framework, as opposed to the optional library that they are
in now.

Bug: 30290416
Test: Manual
Change-Id: I4a186d8e910d6d4f711e983ec8d717fc5cbdefab
14 files changed