TF-2877 Create notification data source & repo

lib/main/permissions/permission_service.dart

@@ -0,0 +1,17 @@
+import 'package:permission_handler/permission_handler.dart';
+
+class PermissionService {
+  Future<bool> isGranted(Permission permission) async {
+    final current = await permission.status;
+    switch (current) {
+      case PermissionStatus.granted:
+        return true;
+      case PermissionStatus.denied:
+        final requestResult = await permission.request();
+        final permissionGranted = requestResult == PermissionStatus.granted;
+        return permissionGranted;
+      default:
+        return false;
+    }
+  }
+}