Cleanup macros

[skallweitNV]

The following macros should be revisited. They can either be removed or should maybe renamed with SLANG_RHI_ prefix. These are leftovers from porting from gfx.

SLANG_CUDA_ASSERT_ON_FAIL
SLANG_CUDA_HANDLE_ERROR
SLANG_CUDA_RETURN_ON_FAIL
SLANG_CUDA_RETURN_WITH_REPORT_ON_FAIL
SLANG_DLL_EXPORT
SLANG_DYNAMIC_EXPORT
SLANG_ENABLE_DXBC_SUPPORT
SLANG_ENABLE_DXGI_DEBUG
SLANG_ENABLE_DXVK
SLANG_ENABLE_PIX
SLANG_ENABLE_VKD3D
SLANG_ENABLE_XLIB
SLANG_OPTIX_HANDLE_ERROR
SLANG_OPTIX_RETURN_ON_FAIL
SLANG_RHI_API
SLANG_RHI_API_FUNC
SLANG_RHI_API_FUNC_NAME
SLANG_RHI_DEBUG_SPIRV
SLANG_RHI_DXR
SLANG_RHI_DYNAMIC
SLANG_RHI_DYNAMIC_EXPORT
SLANG_RHI_ENABLE_AFTERMATH
SLANG_RHI_ENABLE_RENDERDOC
SLANG_RHI_EXPORT_AGILITY_SDK
SLANG_RHI_NV_AFTERMATH
SLANG_RHI_NVAPI
SLANG_RHI_USE_DYNAMIC_CUDA
SLANG_VK_CHECK
SLANG_VK_RETURN_FAIL
SLANG_VK_RETURN_NULL_ON_FAIL
SLANG_VK_RETURN_ON_FAIL