[ci skip] add private R/W registry config for CI build caching

modules/docker-registry/config-private.yml

@@ -0,0 +1,27 @@
+version: 0.1
+log:
+  fields:
+    service: registry-private
+storage:
+  cache:
+    blobdescriptor: inmemory
+  filesystem:
+    rootdirectory: /var/lib/registry
+    maxsize: 100GiB
+  delete:
+    enabled: true
+  maintenance:
+    uploadpurging:
+      enabled: true
+      age: 168h
+      interval: 4h
+      dryrun: false
+http:
+  addr: :5000
+  headers:
+    X-Content-Type-Options: [nosniff]
+health:
+  storagedriver:
+    enabled: true
+    interval: 10s
+    threshold: 3