This switches most remaining HALs to the _client/_server approach.
To unblock efforts blocked on majority of HALs having to use this
model, this change does not remove unnecessary rules from clients of
these HALs. That work will be performed in follow-up commits. This
commit only adds allow rules and thus does not break existing
functionality.

The HALs not yet on the _client/_server model after this commit are:
* Allocator HAL, because it's non-trivial to declare all apps except
  isolated apps as clients of this HAL, which they are.
* Boot HAL, because it's still on the non-attributized model and I'm
  waiting for update_engine folks to answer a couple of questions
  which will let me refactor the policy of this HAL.

Test: mmm system/sepolicy
Test: Device boots, no new denials
Test: Device boots in recovery mode, no new denials
Bug: 34170079
Change-Id: I03e6bcec2fa02f14bdf17d11f7367b62c68a14b9

hal_*_default daemons whose policy is in common/device-agnostic policy
are provided by the vendor image (see vendor/file_contexts). Thus,
their policy should also reside in the vendor image, rather than in
the system image. This means their policy should live in the vendor
subdirectory of this project.

Test: Device boots and appears to work
Bug: 34135607
Bug: 34170079
Change-Id: I6613e43733e03d4a3d4726f849732d903e024016

This marks all HAL domain implementations with the haldomain attribute
so that rules can be written which apply to all HAL implementations.

This follows the pattern used for appdomain, netdomain and
bluetoothdomain.

Test: No change to policy according to sesearch.
Bug: 34180936
Change-Id: I0cfe599b0d49feed36538503c226dfce41eb65f6

The following are the avc denials that are addressed:

avc: denied { call } for pid=889 comm="system_server"
scontext=u:r:system_server:s0 tcontext=u:r:hal_gnss_default:s0
tclass=binder permissive=0

avc: denied { call } for scontext=u:r:hal_gnss_default:s0
tcontext=u:r:system_server:s0 tclass=binder permissive=0

avc: denied { read } for name="hw" dev="mmcblk0p43" ino=1837
scontext=u:r:hal_gnss_default:s0 tcontext=u:object_r:system_file:s0
tclass=dir permissive=0

avc: denied { open } for path="/system/lib64/hw" dev="mmcblk0p43"
ino=1837 scontext=u:r:hal_gnss_default:s0
tcontext=u:object_r:system_file:s0 tclass=dir permissive=0

Bug:31974439

Test: Checked that there no more related avc denial messages related to
the GNSS HAL in dmesg.

Change-Id: I5b43dc088017a5568dd8e442726d2bf52e95b1d5