[pagex] implement visibility flags

[voidcannon] migrate to visibility flags

content/collections/gramophone.pagex.js

@@ -1,4 +1,9 @@
-import {VoidcannonCollectionColor, VoidcannonCollectionIconType, VoidcannonContentType} from "voidcannon";
+import {
+    VoidcannonCollectionColor,
+    VoidcannonCollectionIconType,
+    VoidcannonContentType,
+    VoidcannonVisibilityFlags
+} from "voidcannon";
 import {PagexResourceTransformer} from "pagex";
 
 export default {
@@ -13,5 +18,8 @@ export default {
             _transform: PagexResourceTransformer.MEDIA,
             path: "./assets/gramophone.png"
         }
-    }
+    },
+    visibility_flags: [
+        VoidcannonVisibilityFlags.HIDDEN_IN_SITEMAP,
+    ],
 }