remove dead endpoint staging mode (obsoleted by demo mode)

lib/model/endpoint_data.dart

@@ -1,18 +1,3 @@
-import 'account_data.dart';
-
-enum EndpointMode { live, stage }
-
-class EndpointOptions {
-  Endpoint live;
-  Endpoint? staged;
-  EndpointOptions({required this.live, required this.staged});
-
-  Endpoint get(EndpointMode mode) {
-    if (staged == null || mode == EndpointMode.live) return live;
-    return staged!;
-  }
-}
-
 class Endpoint {
   String domain;
   String path;
@@ -29,13 +14,5 @@ class EndpointData {
 
   EndpointData._construct();
 
-  EndpointMode getEndpointMode() =>
-      AccountData().getUsername().startsWith('google')
-      ? EndpointMode.stage
-      : EndpointMode.live;
-
-  Endpoint nextcloud() => EndpointOptions(
-    live: Endpoint(domain: 'cloud.marianum-fulda.de'),
-    staged: Endpoint(domain: 'mhsl.eu', path: '/marianum/marianummobile/cloud'),
-  ).get(getEndpointMode());
+  Endpoint nextcloud() => Endpoint(domain: 'cloud.marianum-fulda.de');
 }