add new methods to IRecentFilesService.cs

src/KeyKeeper/Services/IRecentFilesService.cs

@@ -8,9 +8,10 @@ public interface IRecentFilesService
     // files are stored in reverse chronological order
     ObservableCollection<RecentFile> RecentFiles { get; }
 
+    void Load();
+    void Save();
+
     void Remember(string filename);
     void Forget(string filename);
     void ForgetAll();
-
-    // TODO load and store
 }