Make Charon take custom h5 path for pythia pre-computed table

[eliotgenton]

Hello,
I was wondering if charon could be modified to be able to take in a custom path for one of the hdf5 table such that one could use say a smoothed table to the neutrino spectrum at this location

https://github.com/icecube/charon/blob/5bc58fa2156932865ea6d1dbd88d51cef24befbe/charon/propa.py#L423

ty !