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

Addresses
avc:  denied  { find } for service=vrmanager pid=472 uid=1000
scontext=u:r:surfaceflinger:s0 tcontext=u:object_r:vr_manager_service:s0
tclass=service_manager

Test: Marlin builds and boots. Denial no longer observed.
Bug: 35258608
Bug: 35197529
Change-Id: I480dff3fdaf01f71e29e96f08350f705c6a23bba

Bug: 30989383
Bug: 34731101
Test: manual
Change-Id: Icf9d48568b505c6b788f2f5f456f2d709969fbeb

This leaves only the existence of surfaceflinger domain as public API.
All other rules are implementation details of this domain's policy
and are thus now private.

Test: No change to policy according to sesearch, except for
      disappearance of all allow rules to do with
      surfaceflinger_current except those created by other domains'
      allow rules referencing surfaceflinger domain from public and
      vendor policies.
Bug: 31364497

Change-Id: I177751afad82ec27a5b6d2440cf0672cb5b9dfb8

Divide policy into public and private components.  This is the first
step in splitting the policy creation for platform and non-platform
policies.  The policy in the public directory will be exported for use
in non-platform policy creation.  Backwards compatibility with it will
be achieved by converting the exported policy into attribute-based
policy when included as part of the non-platform policy and a mapping
file will be maintained to be included with the platform policy that
maps exported attributes of previous versions to the current platform
version.

Eventually we would like to create a clear interface between the
platform and non-platform device components so that the exported policy,
and the need for attributes is minimal.  For now, almost all types and
avrules are left in public.

Test: Tested by building policy and running on device.

Change-Id: Idef796c9ec169259787c3f9d8f423edf4ce27f8c