Use LOCATION_MODE to control location

Completely deprecate LOCATION_PROVIDERS_ALLOWED (but still support it).
Adds additional locking and @GuardedBy annotations where appropriate,
and some minor code cleanup is copied from previous CLs.

Bug: 118885128
Test: Manual + CTS
Change-Id: I3c0b4b2354a4c2b6a120fc467af60cb3409dd671
12 files changed