Revert the Metal Experiment (#701)

Metal sounded like a good idea to get in the emulator but frankly I
underestimated just how experimental and not ready it was.
From my write up in the Discord:
```
As is, Metal supports only a few games.
The games it does support freeze on first use of not playing them via Vulkan, because shader translation is broken.
So you need to use a dirty hack to not delete all your shaders.
Not to mention it breaks many games via MoltenVK because of changes to the shared GPU code.

Merging Metal seemed like a great idea, because of the few games it does support.
But I don't think it's worth it. Many of the games it breaks via MoltenVK *don't work via Metal*. 
Which effectively makes current Ryubing worse for Mac users than Ryujinx 1.1.1403.

I think what I'm gonna do is revert Metal, and reopen it as a PR. That way, you can still take advantage of the Metal backend as is, but without making other games worse with no solution.
```

For what it's worth, the shader translation part could at least be
"fixed" by always applying a 30ms delay for shader translation to Metal.
That being said, that solution sucks ass.
The MoltenVK regressions are even worse.



I hope this is not a let down to the Mac users. I hope you realize I'm
reverting this because you're actively getting a worse experience with
it in the emulator.

src/Ryujinx.Graphics.Shader/SamplerType.cs

@@ -155,51 +155,5 @@ namespace Ryujinx.Graphics.Shader
 
             return typeName;
         }
-
-        public static string ToMslTextureType(this SamplerType type, AggregateType aggregateType, bool image = false)
-        {
-            string typeName;
-
-            if ((type & SamplerType.Shadow) != 0)
-            {
-                typeName = (type & SamplerType.Mask) switch
-                {
-                    SamplerType.Texture2D => "depth2d",
-                    SamplerType.TextureCube => "depthcube",
-                    _ => throw new ArgumentException($"Invalid shadow texture type \"{type}\"."),
-                };
-            }
-            else
-            {
-                typeName = (type & SamplerType.Mask) switch
-                {
-                    SamplerType.Texture1D => "texture1d",
-                    SamplerType.TextureBuffer => "texture_buffer",
-                    SamplerType.Texture2D => "texture2d",
-                    SamplerType.Texture3D => "texture3d",
-                    SamplerType.TextureCube => "texturecube",
-                    _ => throw new ArgumentException($"Invalid texture type \"{type}\"."),
-                };
-            }
-
-            if ((type & SamplerType.Multisample) != 0)
-            {
-                typeName += "_ms";
-            }
-
-            if ((type & SamplerType.Array) != 0)
-            {
-                typeName += "_array";
-            }
-
-            string format = aggregateType switch
-            {
-                AggregateType.S32 => "int",
-                AggregateType.U32 => "uint",
-                _ => "float"
-            };
-
-            return $"{typeName}<{format}{(image ? ", access::read_write" : string.Empty)}>";
-        }
     }
 }