Add export menu item to DeliveryAdminWindow

Elwig/Windows/DeliveryAdminWindow.xaml.cs

@@ -114,6 +114,10 @@ namespace Elwig.Windows {
             await doc.Print();
         }
 
+        private void Menu_Export_Bki_Click(object sender, RoutedEventArgs evt) {
+
+        }
+
         private void OnSecondPassed(object? sender, EventArgs? evt) {
             if (IsReceipt && IsCreating) {
                 var now = DateTime.Now;