private async void reset_btn_Click(object sender, RoutedEventArgs e)
{
DataStorage.INSTANCE.settingsData = new Ausgaben_Rechner.Classes.Data.SettingsData();
DataStorage.INSTANCE.userData = new Ausgaben_Rechner.Classes.Data.UserData();
DataStorage.INSTANCE.saveAllData();
await Utillities.showMessageBoxAsync("App got successfully reset!");
}