Add implementation details to CI summary

[mkannwischer]

We have multiple implementations for NTTs and Keccak now. They are being selected in header files, e.g., here.

It would be great if the Github action summary would include which implementations are being used -- this will make it much easier to debug if we are actually running the correct implementation.
I'm not sure what is the best way to implement that. Ideally one should also be able to determine it easily locally.

[mkannwischer]

I think this is not strictly necessary for the alpha-release and it seems we need some more discussion of what we actually want.

Moving to the next release.