Transplant the Logging system from Telecom

This change is the preliminary transplant of the functionality from
Telecom into android.telecom. It is currently not being used
anywhere and is not hooked into Telecom yet. It will be after this
change is committed.

Test: Refactoring CL. Existing tests still pass
Bug: 26571395
Change-Id: I406975e686c6eaab7e31b1efa426b3406c8e90cf