Duty Cycling and Low Power Mode GNSS feature implementations

Implementaion of 2 GNSS Android-P features:
- The Duty Cycling API to enable high accuracy applications development
- The Low Power Mode GNSS API to save power when indoor

Bug: 64009176
Test: Existing unit tests still pass.
Change-Id: I3ba3b86a635a54927c694fdd66a038757e843937