Conex output pull request

[Jorgecvb1]

Implementation of the possibility to have a conex-like output of the nuspace simulation as .root file.
If is set to 1 in the xml input file, the eas part of the simulation will be writing the slant depth, height and number of particles profiles to a file, which will then be read by the conex_out.py module. This module will read this data together with other data from the results tables, perform a Gaisser-Hillas 6-parameter fit, and write all the relevant information to a .root file following the output format of Conex 2.51.

It adds a dependency to uproot.

[Areustle]

Okay I've looked this over and I think it's good, but will require some alterations.

• - The conexoutput config option should be a commandline flag as well.
• - Before going to release, should transition away from the showerdata.csv file mechanism. Writing the data to disk in parallel is error-prone, due to data-race conditions. Can also cause performance slowdowns and bugs if the layers & events are written out-of-order. Should rewrite the EAS cphotang functions to build up and return variable-length arrays, probably with awkward.
• - Write the variable length arrays out to the sim Results table object using the existing support functions here: https://docs.astropy.org/en/stable/io/fits/usage/unfamiliar.html#variable-length-array-tables
• - Finally, write the conex output uproot file by reading from the sim table, rather than the showerdata.csv file.

Good work and a good use of both uproot and awkward array, which I wasn't familiar with before 👍