Subannotations for specific groups

[ChristianKniep]

In my initial brainstorming of annotation I was coming up with a definition which defines a vendor (or an implementation of MPI) in one annotation. This leads to another annotation being parsed.
So the definition of CUDA would appear under .nvidia.cuda.version:
https://github.com/supercontainers/compspec/blob/6764db83a00974ff590a41292df597e72c733a79/supercontainers/compspec.json#L14

Like:

gpu.vendor = nvidia
gpu.nvidia.cuda.version = 12.1

Not sure if that is the best approach, as we might just assume that if the gpu.nvidia.cuda.version entry exists it is present. For containers which are even able to support both a selector (defining which vendor to go with) might be a hinderance.

[vsoch]

I like the idea of having them be a graph that is flattened out - and I do think what we have here will ultimately change! Let's keep it dumb and simple for now, share these ideas with the working group when it comes up, and then we will do another sweep / update for what the group eventually decides.