Start Metal Backend

Revert build yml changes

src/Ryujinx/UI/Renderer/EmbeddedWindowMetal.cs

@@ -0,0 +1,25 @@
+using SPB.Windowing;
+using SPB.Platform.Metal;
+using System;
+
+namespace Ryujinx.UI.Renderer
+{
+    public class EmbeddedWindowMetal : EmbeddedWindow
+    {
+        public SimpleMetalWindow CreateSurface()
+        {
+            SimpleMetalWindow simpleMetalWindow;
+
+            if (OperatingSystem.IsMacOS())
+            {
+                simpleMetalWindow = new SimpleMetalWindow(new NativeHandle(NsView), new NativeHandle(MetalLayer));
+            }
+            else
+            {
+                throw new PlatformNotSupportedException();
+            }
+
+            return simpleMetalWindow;
+        }
+    }
+}