Add nearby to tethering apex

Nearby will be merged together with the tethering/connectivity APEX, so
that module maintenance efforts can be reduced, and the two codebases
can evolve the interfaces that they expose to each other over time.

Bug: 189355156
Test: m
Ignore-AOSP-First: Nearby is not yet in AOSP. This introduces minimal
                   unavoidable merge conflicts until it is merged there.
Change-Id: If4b40689a257d2806f895cd2dded97fc699adc5f
6 files changed