Add NVTX

This contains the NVTX ranges to get more structure into the profiles. The snippets and macros are from the blog post at https://developer.nvidia.com/blog/cuda-pro-tip-generate-custom-application-profile-timelines-nvtx/

I marked this as Draft as I just noticed that it probably makes sense to exclude the profile commands text file. In any case now you can already see the code changes so we can discuss at our call.