[cuda] Export vcpkg_find_cuda.cmake

[ras0219]

This PR introduces a port-packaged helper vcpkg_find_cuda() that works similarly to vcpkg_find_fortran():

# ports/some_consumer/portfile.cmake

include(${CURRENT_INSTALLED_DIR}/share/vcpkg_find_cuda/vcpkg_find_cuda.cmake)
vcpkg_find_cuda(OUT_CUDA_TOOLKIT_ROOT CUDA_TOOLKIT_ROOT)
vcpkg_configure_cmake(
  SOURCE_PATH "${SOURCE_PATH}"
  OPTIONS -DCUDA_TOOLKIT_ROOT=${CUDA_TOOLKIT_ROOT}
)

@cenit and @Neumann-A for their CUDA expertise on whether this approach seems correct

[JackBoosY]

Need test locally.

[Neumann-A]

Is there a reason not to go full vcpkg_find_fortran and use CMakeDetermineCUDACompiler.cmake ? Just trick it to ingore the FATAL_ERROR by setting CMAKE_GENERATOR to Ninja

[Neumann-A]

Instead of search in all those dirs env CUDA_PATH is actually required by CMake. As such setting up CUDA_PATH if one of the other env variables exist is the way to go since it mitigates the env removal some VS updates seem to do.

[JackBoosY]

We should use the provided FindCUDA.cmake cmake, but it is not suitable for our expected CUDA path.

[Neumann-A]

We should use the provided FindCUDA.cmake cmake, but it is not suitable for our expected CUDA path.

We need to differentiate between the CUDA compiler and the CUDA libraries.

[cenit]

We should use the provided FindCUDA.cmake

FindCUDA.cmake is deprecated. I would not build a vcpkg feature on top of that

[Neumann-A]

Relevant:
https://cmake.org/cmake/help/latest/module/FindCUDA.html
https://cmake.org/cmake/help/latest/module/FindCUDAToolkit.html

[BillyONeal]

Thanks for your contribution!