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.Metal/BufferUsageBitmap.cs

@@ -1,85 +0,0 @@
-using System.Runtime.Versioning;
-
-namespace Ryujinx.Graphics.Metal
-{
-    [SupportedOSPlatform("macos")]
-    internal class BufferUsageBitmap
-    {
-        private readonly BitMap _bitmap;
-        private readonly int _size;
-        private readonly int _granularity;
-        private readonly int _bits;
-        private readonly int _writeBitOffset;
-
-        private readonly int _intsPerCb;
-        private readonly int _bitsPerCb;
-
-        public BufferUsageBitmap(int size, int granularity)
-        {
-            _size = size;
-            _granularity = granularity;
-
-            // There are two sets of bits - one for read tracking, and the other for write.
-            int bits = (size + (granularity - 1)) / granularity;
-            _writeBitOffset = bits;
-            _bits = bits << 1;
-
-            _intsPerCb = (_bits + (BitMap.IntSize - 1)) / BitMap.IntSize;
-            _bitsPerCb = _intsPerCb * BitMap.IntSize;
-
-            _bitmap = new BitMap(_bitsPerCb * CommandBufferPool.MaxCommandBuffers);
-        }
-
-        public void Add(int cbIndex, int offset, int size, bool write)
-        {
-            if (size == 0)
-            {
-                return;
-            }
-
-            // Some usages can be out of bounds (vertex buffer on amd), so bound if necessary.
-            if (offset + size > _size)
-            {
-                size = _size - offset;
-            }
-
-            int cbBase = cbIndex * _bitsPerCb + (write ? _writeBitOffset : 0);
-            int start = cbBase + offset / _granularity;
-            int end = cbBase + (offset + size - 1) / _granularity;
-
-            _bitmap.SetRange(start, end);
-        }
-
-        public bool OverlapsWith(int cbIndex, int offset, int size, bool write = false)
-        {
-            if (size == 0)
-            {
-                return false;
-            }
-
-            int cbBase = cbIndex * _bitsPerCb + (write ? _writeBitOffset : 0);
-            int start = cbBase + offset / _granularity;
-            int end = cbBase + (offset + size - 1) / _granularity;
-
-            return _bitmap.IsSet(start, end);
-        }
-
-        public bool OverlapsWith(int offset, int size, bool write)
-        {
-            for (int i = 0; i < CommandBufferPool.MaxCommandBuffers; i++)
-            {
-                if (OverlapsWith(i, offset, size, write))
-                {
-                    return true;
-                }
-            }
-
-            return false;
-        }
-
-        public void Clear(int cbIndex)
-        {
-            _bitmap.ClearInt(cbIndex * _intsPerCb, (cbIndex + 1) * _intsPerCb - 1);
-        }
-    }
-}