Create full offline search script

There is a need to create a native offline search, possibly as a bin script. This would load gpstimes of external events from a .txt or similar file, look for coincidences around these times, and if found, try to download a skymap from GraceDB and calculate a joint FAR. This would, in principle, be able to cover events from an entire operating run or more.

This could be adapted from a pre-existing but similar code found here: https://ldas-jobs.ligo.caltech.edu/~brandon.piotrzkowski/FRB-Raven_skymap_search/