Update example documentation

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

example/lib/services/demo_service.dart

@@ -1,33 +0,0 @@
-import "package:arcane_framework/arcane_framework.dart";
-import "package:flutter/foundation.dart";
-import "package:uuid/uuid.dart";
-
-class IdService extends ArcaneService {
-  static final IdService _instance = IdService._internal();
-  static IdService get I => _instance;
-
-  IdService._internal();
-
-  bool _initialized = false;
-  bool get initialized => I._initialized;
-
-  String? _sessionId;
-  ValueListenable<String?> get sessionId =>
-      ValueNotifier<String?>(I._sessionId);
-
-  String get newId => uuid.v7();
-
-  /// The `Uuid` instance used for generating unique IDs.
-  static const Uuid uuid = Uuid();
-
-  Future<void> init() async {
-    Arcane.log(
-      "Initializing ID Service",
-      level: Level.debug,
-    );
-
-    I._sessionId = uuid.v7();
-    I._initialized = true;
-    notifyListeners();
-  }
-}