Only show the official signature activity in the "local" env

So only during development. Also rewrite the application description
to not mention the official signature.

assets/vpu-signature.topic.metadata.json → assets/vpu-signature.topic.metadata.json.ejs

@@ -8,12 +8,13 @@
     "en": "Signatureservice"
   },
   "description": {
-    "de": "Mit dieser Applikation können Sie, sofern Sie dazu berechtigt sind, PDF-Dateien im Namen der TU Graz signieren",
-    "en": "With this application you can, provided you are authorized to do so, sign PDF-files in the name of the TU Graz"
+    "de": "Mit dieser Applikation können Sie PDF Dokumente signieren",
+    "en": "With this application you can sign PDF documents"
   },
   "routing_name": "signature",
   "activities": [
-    {"path": "vpu-official-signature-pdf-upload.metadata.json"},
+    {"path": "vpu-official-signature-pdf-upload.metadata.json",
+     "visible": <%= environment == "local" %>},
     {"path": "vpu-qualified-signature-pdf-upload.metadata.json"}
   ],
   "attributes": []