add ad services and Docker configuration for web app

lib/services/ad_service.dart

@@ -0,0 +1,19 @@
+import "package:flutter/widgets.dart";
+
+abstract class AdService {
+
+  /// Initialize ad SDK
+  Future<void> initialize();
+
+  /// Load banner ad
+  Future<void> loadBannerAd();
+
+  /// Get banner widget to display
+  Widget getBannerWidget();
+
+  /// Dispose resources
+  void dispose();
+
+  /// Check if ads are loaded
+  bool get isLoaded;
+}