Pick export dir + auto-export (#283, #600)

lib/pages/apps.dart

@@ -74,11 +74,6 @@ class AppsPageState extends State<AppsPage> {
         setState(() {
           refreshingSince = null;
         });
-        if (settingsProvider.autoExportOnUpdateCheckKeepNum > 0) {
-          appsProvider.exportApps(isAuto: true).then((value) {
-            appsProvider.trimAutoExports();
-          });
-        }
       });
     }