TF-524 Create RecentSearchCache and TypeAHeadQuickSearch widget

lib/features/mailbox_dashboard/domain/model/recent_search.dart

@@ -0,0 +1,12 @@
+
+import 'package:equatable/equatable.dart';
+
+class RecentSearch with EquatableMixin {
+  final String value;
+  final DateTime creationDate;
+
+  RecentSearch(this.value, this.creationDate);
+
+  @override
+  List<Object?> get props => [value, creationDate];
+}