MG LO GP python2 fix
Restores python2 compatibility for MG5_aMC 2.9.3+. No longer use "bin/run.sh" wrapper script (which calls ./bin/gridrun) but directly use "python bin/gridrun" and perform environment setup and moving of events in python.
Please be advised that registry.cern.ch registry (Registry Service) will be unavailable next Monday, March 10th starting at 08:00h (Geneva time) for a short period of time. This may cause temporary disruptions to your workflows. Further information: OTG0154905
Restores python2 compatibility for MG5_aMC 2.9.3+. No longer use "bin/run.sh" wrapper script (which calls ./bin/gridrun) but directly use "python bin/gridrun" and perform environment setup and moving of events in python.