simplify: dedupe boilerplate and remove dead code across all layers

lib/view/pages/settings/sections/about_section.dart

@@ -1,7 +1,6 @@
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
-import 'package:jiffy/jiffy.dart';
 import 'package:package_info_plus/package_info_plus.dart';
 
 import '../../../../state/app/modules/settings/bloc/settings_cubit.dart';
@@ -71,7 +70,7 @@ class AboutSection extends StatelessWidget {
       applicationLegalese:
           'Alles für deinen Schulalltag am Marianum Fulda.\n\n'
           "${kReleaseMode ? "Production" : "Development ${kProfileMode ? "(Profiling)" : "(Debug)"}"} build.\n\n"
-          'Marianum Fulda\n2019-2020 & 2022-${Jiffy.now().year}\nElias Müller',
+          'Marianum Fulda\n2019-2020 & 2022-${DateTime.now().year}\nElias Müller',
     );
   }