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.te b/private/service.te
index 2ab6335..006183e 100644
--- a/private/service.te
+++ b/private/service.te
@@ -11,3 +11,4 @@
 type statsmanager_service,          system_api_service, system_server_service, service_manager_type;
 type tracingproxy_service,          system_server_service, service_manager_type;
 type uce_service,                   service_manager_type;
+type compos_internal_service,       service_manager_type;