Draft: Adding test for CA-based Gen_tf with MadGraph and Pythia

@tadej this is just an example to start the discussion.

First thing we should discuss is whether we should move all the calls of the MadGraphUtils functions to MadGraphControl/__init__.py in an execute function and have the jO only calling

import MadGraphControl as MG
mg = MG.MadGraph(flags=flags, evgenConfig=self)

perhaps with further settings, so that the execute() function knows what to execute and how.

Second thing we should discuss is how to update MadGraphControl since currently they use runArgs a lot in the code and overwriting it with runArgs=flags is not going to work. Updating the MadGraphControl modules as done here, will break all the existing jO, so it's probably not what we want to do.