After discussions with experts we determined that it would be best to only use Fatras for Inner Detector simulation, so this
merge request updates the ATLFAST3F_G4MS configuration to use Geant4 rather than Fatras to simulate particles in the Calorimeter
which are not passed to FastCaloSim/FastCaloGAN (mainly this effects muons and long-lived exotic particles).
The configuration of ATLFAST3F_G4MS should now match the ATLFAST3 simulator configuration, except for the simulator used in the Beam Pipe and Inner Detector, where Fatras rather than Geant4 is used in ATLFAST3F_G4MS.