Deployment of GN2XTauv00

The goal of this MR is to implement GN2XTauv00 output scores in PHYS derivations.

The following tests were performed:

• Consistency checks between training-dataset-dumper (running on Athena) and salt (the training framework for ftag GNNs) following this salt documentation and showed expected consistency between outputs scores from the 2 evaluations.
• Check that the output scores were written in PHYS derivations with the changes of this MR, done by Thomas @tstreble (thanks again ).

Would that sounds good to you @svanstro, @hartman, @dguest, @vvecchio? Thanks a lot in advance!

I keep it as draft for now since the model is not yet in the main area (so the path given in BTagConfig.py is just an example).

Tagging @mfujimot @tstreble @lcadamur.