Use Silk.NET.Maths in OpenXR

[Perksey]

We have our own Maths types, but it seems we've generated bindings for OpenXR's maths types and are using them instead.

We should remove our bindings for the OpenXR maths types and use typemaps to use Silk.NET.Maths' types instead.

[Perksey]

for info @Exanite not sure if we still want to do this

[Exanite]

Yup, I saw this. This is why I have the really long review comment here with a list of potentially relevant types: #2590 (comment)

[Exanite]

I'm leaning towards handling these in some way. Either by adding casts where possible or by directly remapping these types.
Not doing so would be annoying having to copy from a Silk/Numerics type to the corresponding API-specific type.

[Perksey]

I'd just remap them tbh, we did this in some places in 2.0 and never heard a complaint. This issue is mostly an oversight in 2.0.