Separate Phone Policy from mechanism

Create a new policy file which interacts using either public APIs (such
as Intents) or uses equivalent functions which are exposed by the
binder. This is an attempt to be able to separate policy such that
different devices can have different policies.

Bug: b/33079907
Test: JUnit tests
Change-Id: I6c5a7ee9eb4e10f5f649794546acde5ec4b297aa