Brought MadGraphControl in master up-to-speed with 21.6
Includes commits addressing the following issues
- Remove hacking of the "run.sh" script for LO gridpacks, instead add reweighting in standalone mode
- Fix an issue where MG would use the wrong lhapdf-config
- Fix case sensitivity issue for decay settings
- Completely removed above "run.sh" script and run gridpacks from directly from python instead of using intermediate shell script
- updated py2-specific solutions to py3
- Removed setting of "loop" parameter (corresponding to mu_R), which is hidden in newer MG versions and only affects standalone MadLoop but not event generation, for which mu_R is set from run_card