AudioService: internal API for disabling audio playback for a UID

Internal API, available through AudioManagerInternal, to flag
  a UID as having lost the ability to play audio. When that
  happens, all players associated with this UID are paused, and
  future players are immediately paused when they report they
  started.
Users of this API must "enable" a previously banned UID when
  it is no longer in use.

Test: upcoming manual test with background apps
Bug: 34471029
Change-Id: Ic1c103aabe8f3897072b3ce938d84cb949540e23