Use DXC to compile shaders

[codeonwort]

I wrote shader loading code 4 years ago and forgot about it. It was using FXC and SM5, so let's replace it with DXC amd SM6. Also this PR is a stepping stone for DXR which requires SM6.3.

References

• https://github.com/microsoft/DirectXShaderCompiler/wiki/Using-dxc.exe-and-dxcompiler.dll
• https://asawicki.info/news_1719_two_shader_compilers_of_direct3d_12
• https://simoncoenen.com/blog/programming/graphics/DxcCompiling

Note

When I invoke IDxcCompiler3::Compile() I get following exceptions:

Exception thrown at 0x00007FF9CBAC039C in TestApplication.exe: Microsoft C++ exception: hlsl::Exception at memory location 0x00000058243DADB0.
Exception thrown at 0x00007FF9CBAC039C in TestApplication.exe: Microsoft C++ exception: hlsl::Exception at memory location 0x00000058243DAB60.
Exception thrown at 0x00007FF9CBAC039C in TestApplication.exe: Microsoft C++ exception: hlsl::Exception at memory location 0x00000058243DAB60.

But the applicatoin runs fine. Don't know the reason yet.