FEATURE add mock server and main_dev.dart for developement

lib/main.dart

@@ -121,6 +121,7 @@ void main() async {
   });
 
   final apiFactory = PaperlessApiFactoryImpl(sessionManager);
+
   runApp(
     MultiProvider(
       providers: [

lib/main_dev.dart

@@ -0,0 +1,10 @@
+
+
+import 'package:mock_server/mock_server.dart';
+import 'package:paperless_mobile/main.dart' as ParentMain;
+
+void main() async {
+  await LocalMockApiServer().start();
+  ParentMain.main();
+}
+