Move docker-registry.yml into submodule

Change-Id: I2ebbf2fb89a844825796e1ca2332010d2a435bf4
diff --git a/init.yml b/init.yml
index 6d3ed47..55bfa47 100644
--- a/init.yml
+++ b/init.yml
@@ -34,7 +34,7 @@
 - service.docker.host
 - system.docker.swarm.manager
 - system.docker.swarm.master
-- cluster.mcp-offline.infra.docker-registry
+- cluster.mcp-offline.infra.mirror.docker-registry
 - service.docker.host
 parameters:
   _param: