Schematize Telephony System Properties

Properties accessed across partitions are now schematized and will
become APIs to make explicit interfaces among partitions.

Bug: 117924132
Bug: 141246285
Test: lunch blueline-userdebug; m checkbuild
Change-Id: I7e8e7dc77a98aeec2dbb73e00c5481ca0cb1a586
Merged-In: I7e8e7dc77a98aeec2dbb73e00c5481ca0cb1a586
(cherry picked from commit 7bcc995f)