refactor setting providers; include content blocking settings;

packages/flutter_mozilla_components/lib/src/domain/services/gecko_browser.dart

@@ -13,8 +13,8 @@ class GeckoBrowserService {
 
   GeckoBrowserService({GeckoBrowserApi? api}) : _api = api ?? _apiInstance;
 
-  Future<void> initialize(LogLevel logLevel) {
-    return _api.initialize(logLevel);
+  Future<void> initialize(LogLevel logLevel, ContentBlocking contentBlocking) {
+    return _api.initialize(logLevel, contentBlocking);
   }
 
   Future<bool> showNativeFragment() {

packages/flutter_mozilla_components/lib/src/domain/services/gecko_engine_settings.dart

@@ -84,4 +84,10 @@ class GeckoEngineSettingsService {
       GeckoEngineSettings(webContentIsolationStrategy: state),
     );
   }
+
+  Future<void> contentBlocking(ContentBlocking state) {
+    return _api.updateRuntimeSettings(
+      GeckoEngineSettings(contentBlocking: state),
+    );
+  }
 }