Vecgeom 329
Finish VecGeom-329. Remove/Replace VECGEOM_NVCC and VECGEOM_NVCC_DEVICE, Rename/Clarify VECGEOM_CUDA to VECGEOM_ENABLE_CUDA (as VECGEOM_NVCC becomes VECCORE_CUDA)
Finish VecGeom-329. Remove/Replace VECGEOM_NVCC and VECGEOM_NVCC_DEVICE, Rename/Clarify VECGEOM_CUDA to VECGEOM_ENABLE_CUDA (as VECGEOM_NVCC becomes VECCORE_CUDA)