Split composd's service in two

They are served by the same process but have different clients:
- the main interface is exposed to system server;
- the internal interface is called by odrefresh when spawned by composd.

Test: compos_cmd forced-compile-test
Bug: 199147668
Change-Id: Ie1561b7700cf633d7d5c8df68ff58797a8d8bced
diff --git a/private/service_contexts b/private/service_contexts
index 0e723f2..f833096 100644
--- a/private/service_contexts
+++ b/private/service_contexts
@@ -76,6 +76,7 @@
 android.security.remoteprovisioning       u:object_r:remoteprovisioning_service:s0
 android.service.gatekeeper.IGateKeeperService    u:object_r:gatekeeper_service:s0
 android.system.composd                    u:object_r:compos_service:s0
+android.system.composd.internal           u:object_r:compos_internal_service:s0
 android.system.virtualizationservice      u:object_r:virtualization_service:s0
 app_binding                               u:object_r:app_binding_service:s0
 app_hibernation                           u:object_r:app_hibernation_service:s0