Add a fat binary for MoltenVK on macOS

[Perksey]

Should also include the ICD JSON so it can be paired with Silk.NET.Vulkan.Loader.Native.

This should be done before 2.18 is released because it's an easy win.

[Perksey]

As @alexrp pointed out in #2012, I did this here: 7c6d2eb

So this can be closed when that PR is merged.