sepolicy: add version_policy tool and version non-platform policy.

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
diff --git a/private/drmserver.te b/private/drmserver.te
index 340c454..cc96afd 100644
--- a/private/drmserver.te
+++ b/private/drmserver.te
@@ -1,3 +1,5 @@
 # type_transition must be private policy the domain_trans rules could stay
 # public, but conceptually should go with this
 init_daemon_domain(drmserver)
+
+type_transition drmserver apk_data_file:sock_file drmserver_socket;