Provide a way to create questions without creating a class

[Galad]

Just like with the Actions class, a Questions class should permit to create a question without having to create a class:

public static IQuestion<int> RemainingItems()
{
   return Questions.Create(
      "Remaining items", 
      actor => actor.AsksFor(TextContent.Of(ToDoPage.ToDoItemsLeftCounter).AsInteger()))
      );
}

An overload with an ability should also be available.