TF-1202: Configure FCM

lib/features/push_notification/data/datasource/firebase_datasource.dart

@@ -0,0 +1,9 @@
+import 'package:model/firebase/firebase_dto.dart';
+
+abstract class FirebaseDatasource {
+  Future<FirebaseDto> getCurrentFirebase();
+
+  Future<void> setCurrentFirebase(FirebaseDto newCurrentFirebase);
+
+  Future<void> deleteCurrentFirebase(String token);
+}