Changed file directories, added clear storage setting, updated readme w/ Google Play reference

lib/features/settings/view/widgets/clear_storage_setting.dart

@@ -0,0 +1,23 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_cache_manager/flutter_cache_manager.dart' as cm;
+import 'package:paperless_mobile/core/service/file_service.dart';
+import 'package:paperless_mobile/di_initializer.dart';
+
+class ClearStorageSetting extends StatelessWidget {
+  const ClearStorageSetting({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return ListTile(
+      title: Text("Clear data"),
+      subtitle:
+          Text("Remove downloaded files, scans and clear the cache's content"),
+      onTap: _clearCache,
+    );
+  }
+
+  void _clearCache() async {
+    getIt<cm.CacheManager>().emptyCache();
+    FileService.clearUserData();
+  }
+}