Add changes to bring up Keystore Certificate post processor.

Adds a system property which denotes the presence of a post processor.
Also adds the policies for the post processor service that is needed for
the processor to work correctly.

Test: manual check with test cert processor.
Bug: 361877215
Change-Id: I5feb0a250e2856189d5b4165187dcb415790e529
diff --git a/private/property.te b/private/property.te
index 8cc91e4..fb5251f 100644
--- a/private/property.te
+++ b/private/property.te
@@ -43,6 +43,7 @@
 system_internal_prop(profcollectd_node_id_prop)
 system_internal_prop(radio_cdma_ecm_prop)
 system_internal_prop(remote_prov_prop)
+system_internal_prop(remote_prov_cert_prop)
 system_internal_prop(rollback_test_prop)
 system_internal_prop(setupwizard_prop)
 system_internal_prop(snapshotctl_prop)
@@ -783,6 +784,11 @@
 } remote_prov_prop:property_service set;
 
 neverallow {
+  domain
+  -init
+} remote_prov_cert_prop:property_service set;
+
+neverallow {
   # Only allow init and shell to set rollback_test_prop
   domain
   -init