feat: add gitlab registry

templates/zot/config.json.j2

@@ -97,6 +97,19 @@
               "destination": "/quay"
             }
           ]
+        },
+        {
+          "urls": ["https://registry.gitlab.com"],
+          "onDemand": true,
+          "tlsVerify": true,
+          "maxRetries": 3,
+          "retryDelay": "5m",
+          "content": [
+            {
+              "prefix": "**",
+              "destination": "/gitlab"
+            }
+          ]
         }
       ]
     }