Rewrite host GPU abstraction

- Don't have to repeat the same thing for 4 renderers.
 - Add native Metal renderer.

src/duckstation-qt/displaywidget.h

@@ -2,8 +2,11 @@
 // SPDX-License-Identifier: (GPL-3.0 OR CC-BY-NC-ND-4.0)
 
 #pragma once
+
+#include "util/window_info.h"
+
 #include "common/types.h"
-#include "common/window_info.h"
+
 #include <QtWidgets/QStackedWidget>
 #include <QtWidgets/QWidget>
 #include <optional>