Link empty nearby library into 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.

This is a cherry-pick from downstream branches, with some differences:
 - nearby/Android.bp is added with empty libraries
 - There is no API change, as no API classes are added
 - proguard is not applied, so no proguard rules change
 - HalfSheetUX APK is not added to the APEX

Bug: 189355156
Test: m
Merged-In: If4b40689a257d2806f895cd2dded97fc699adc5f
Change-Id: I2eb965a0965ffce08388278945160e57e8094339
4 files changed