Add runtime HLSL shaders compilation support

[egorodet]

Currently Methane Kit supports only build-time shaders compilation with binary byte-code stored in application resources. In some cases it is more convenient to do runtime shaders compilation from HLSL source code using specific set of macro-definitions.

While it is trivial to support runtime compilation of HLSL to DXIL bytecode for DirectX or HLSL to SPIRV bytecode for Vulkan using DXC compiler dynamic library, yet it is more complicated to convert HLSL to Metal shader code and then compile it to Metal bytecode, because it involves additional use of SPIRV-Cross library for conversion from the compiled SPIRV bytecode to Metal shader source code.