Policy for Camera HAL HwBinder service

This adds restrictions on which domains can register this HwBinder
service with hwservicemanager and which domains can obtain tokens for
this service from hwservicemanager.

Test: Use Google Camera app to take HDR+ photo, conventional photo,
      record video with sound, record slow motion video with sound.
      Check that the photos display correctly and that videos play
      back fine and with sound. Check that there are no SELinux
      denials to do with camera.
Bug: 34454312
Change-Id: Icfaeed917423510d9f97d18b013775596883ff64