Converts SND@LHC digitised simulation files into input data for ML

The conversion has two parts:

1. SND@LHC digitised ROOT files -> numpy arrays (within SND@LHC experiment software environment)
2. numpy arrays -> pyg format (pytorch + pyg environment, where pyg is a pytorch GNN library)

The two-step procedure is needed because the SND@LHC SW setup does not contain pytorch/pyg.

SND Digi -> numpy arrays

Main script: digi_to_ml.py runs the conversion based on passed arguments

Condor batch submission: condor contains a condor submission files and scripts to create parameter lists and to merge the outputs

numpy arrays -> pyg format

Main script: convert_to_pyg.py