Enable quasi-stable particle Simulation in the AthSimulation project

Adding G4Extensions packages without additional dependencies to AthSimulation project. This should allow quasi-stable particle simulation to run in AthSimulation releases. Side benefit is that a number of SUSY/Exotics samples will now also be able to be run with the AthSimulation project.
NB Skipping G4HitFilter as it has dependencies on forward detectors and skipping G4ExternalDecay and RHadrons as they have a dependency on Pythia.
Also switch on relevant tests to allow quasi-stable particle simulation to be monitored in AthSimulation nightlies.
ReSimulation workflow is not supported by the AthSimulation project, due to the lack of the CutFlowSvc - therefore switching off that test (should solve ATLASSIM-5139).