Raytracing shaders with vulkano-shaders

[Atilogit]

This PR adds functionality to compile raytracing shaders.
This was part of a project to add partial raytracing support to vulkano but i didn't get around to finishing it.

The code in vulkano/src/shader/reflect.rs is only a workaround. I didn't have the time to get far enough to do it properly.

* Entries for Vulkano changelog:
    - vulkano-shaders now supports `raygen`, `anyhit`, `closesthit`, `miss`, `intersection` and `callable` shaders

[Rua]

Looks good, thank you! For future reference, the workaround in reflect.rs, what should actually be done there?

[Atilogit]

Not sure. I didn't spend much time with the reflection part of vulkano