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

hwservicemanager can check hwservice_contexts files
both from the framework and vendor partitions.

Initially, have a wildcard '*' in hwservice_contexts
that maps to a label that can be added/found from
domain. This needs to be removed when the proper policy
is in place.

Also, grant su/shell access to hwservicemanager list
operations, so tools like 'lshal' continue to work.

Bug: 34454312
Test: Marlin boots
Change-Id: I3a02d97a82458692b528d85c1b8e78b6f82ea1bc