Themes: add operator question to bicycle parking

assets/layers/bike_parking/bike_parking.json

@@ -677,6 +677,16 @@
         ]
       }
     },
+    {
+      "id": "operator",
+      "question": {
+        "en": "Who maintains this bicycle parking?",
+        "nl": "Wie beheert deze fietsenstalling?"
+      },
+      "freeform": {
+        "key": "operator"
+      }
+    },
     {
       "id": "operator_phone",
       "question": {