Added & using prepared statements for stores

Store/IStore.cs

@@ -7,7 +7,7 @@ namespace HermesSocketServer.Store
         Task Load();
         bool Modify(K? key, Action<V> action);
         void Remove(K? key);
-        Task<bool> Save();
+        Task Save();
         bool Set(K? key, V? value);
     }
 }