Ark shader blockers

[fu5ha]

• - Texture support #204 (implemented by Textures! #276)
• - support proc-macros #192 (fixed by Use rustc_codegen_llvm's get_dylib_metadata to unblock proc macros. #268)
• - Support "interface blocks" #232
• - Support Flat decoration on shader Input/Outputs #314

Part of #36

[Jasper-Bekkers]

1. Running runners with release mode not working is a blocker as well, ends up in infinite loop fixed for now by using separate shader builder crate
2. Subchecked is a problem in weird cases which is fucked for flags. zombie constants/types are merged with normal constants/types #274 fixed by Do not merge zombie and non-zombies #288
3. Bindless arrays are seen as runtime arrays?

layout(set = 0, binding = 1) readonly buffer InstanceDataBuffer {
    InstanceDataEntry instance_data[];
};

4. Missing nointerpolation attribute. (Needed for the flags on the mesh shader)
5. Hacked in multiview capability would be nice? (Only needed for VR - but easy to add)

[khyperia]

• #[spirv(block)], hack fix for Support "interface blocks" #232
• implement strings->panics

[fu5ha]

@khyperia added #314 to this because I think it's blocking for https://github.com/EmbarkStudios/ark/pull/2756 but not sure if that's actually true

[Jasper-Bekkers]

I think we can close this now that most Ark shaders have migrated to rust-gpu.