Adding copyright to LHEFilters python files, and removing one comment
requested to merge atlas-physics/pmg/mcexperts/powheg-experts/athena:21.6-LHEFiltersCopyright into 21.6
This MR is adding copyright statements in the python files of the LHE filters in the Generators/MCJobOptionUtils package. It also removes two lines of commented code.
These modifications were made already in master as requested by the shifter - see !53970 (merged) - so no need to sweep this MR to master.