Merge changes I7065d081,Ic7c3a331,Ia432057b

* changes:
  Add API for tethering clients change
  Allows the caller to specify configuration by TetheringRequest
  Make TetheringManager to system API
tree: 4a34b96bba2a10b9b1a8debdb138033ec669abfb
  1. core/
  2. services/
  3. tests/