Added option to open FileViewer always with system dialog, enabled by default on iOS

lib/view/settings/settings.dart

@@ -139,6 +139,19 @@ class _SettingsState extends State<Settings> {
 
             const Divider(),
 
+            ListTile(
+              leading: const Icon(Icons.open_in_new_outlined),
+              title: const Text("Dateien immer mit Systemdialog öffnen"),
+              trailing: Checkbox(
+                value: settings.val().fileViewSettings.alwaysOpenExternally,
+                onChanged: (e) {
+                  settings.val(write: true).fileViewSettings.alwaysOpenExternally = e!;
+                },
+              ),
+            ),
+
+            const Divider(),
+
             ListTile(
               leading: const Icon(Icons.live_help_outlined),
               title: const Text("Informationen und Lizenzen"),