AtlasAthenaLogFile

Rewritting https://gitlab.cern.ch/atlas/athena/blob/master/Trigger/TrigValidation/TrigValTools/bin/check_log.pl in Python, as nobody uses Perl anymore. https://docs.google.com/document/d/16HEEGWhYffUScxdy72tlqETZ34Hltiy8gydU5vFuckQ/edit?usp=sharing