This leaves the existence of priv_app 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 from priv_app_current
      attribute (as expected) except for
      allow priv_app_current update_engine_current:binder transfer;
      which is caused by public update_engine.te rules and will go
      away once update_engine rules go private.
Bug: 31364497

Change-Id: Iea583127fbf0a19c37dd42bf1ef2ae0454793391

app_domain was split up in commit: 2e00e637 to
enable compilation by hiding type_transition rules from public policy.  These
rules need to be hidden from public policy because they describe how objects are
labeled, of which non-platform should be unaware.  Instead of cutting apart the
app_domain macro, which non-platform policy may rely on for implementing new app
types, move all app_domain calls to private policy.

(cherry-pick of commit: 76035ea0)

Bug: 33428593
Test: bullhead and sailfish both boot. sediff shows no policy change.
Change-Id: I4beead8ccc9b6e13c6348da98bb575756f539665

In order to support platform changes without simultaneous updates from
non-platform components, the platform and non-platform policies must be
split.  In order to provide a guarantee that policy written for
non-platform objects continues to provide the same access, all types
exposed to non-platform policy are versioned by converting them and the
policy using them into attributes.

This change performs that split, the subsequent versioning and also
generates a mapping file to glue the different policy components
together.

Test: Device boots and runs.
Bug: 31369363
Change-Id: Ibfd3eb077bd9b8e2ff3b2e6a0ca87e44d78b1317