Allow LHE only generation in CI

Changes introduced

• Print "- LHEonly = True|False" in logParser
• Transfer information if LHEonly jO is present in run_athena job
• Adjust Gen_tf.py parameters based on whether LHEonly or normal job is run

Tests

To be tested in !678 (merged)

Successful test here: https://gitlab.cern.ch/atlas-physics/pmg/mcjoboptions/-/pipelines/1962222

Issues resolved

Closes #53 (closed)