Upgraded CUDA Support in CMake

[Alec Krawciw]

Since CMake V3.17 CUDA loading has been upgraded.

All of cudpp gpu_surf and vtr_torch use CUDA in CMake. This might be a better way to auto select the GPU. The current version has issues on the GitHub build farms.

https://cmake.org/cmake/help/latest/module/FindCUDAToolkit.html#module:FindCUDAToolkit