This MR refactors the FastCaloSim extrapolation, in preparation of the switch of using the Geant4 track transport instead of the ATLAS tracking tools for the FCS in G4 implementation. Most importantly, the FastCaloSimCaloExtrapolation class is disentangled into a FastCaloSimCaloTransportation class that performs the track transportation with the ATLAS tracking tools (which is to be deprecated in the future) and a FastCaloSimCaloExtrapolation class which now just handles the extrapolation to the ID-Calo boundary and all other calorimter layers.
Simulation was tested for legacy and CA config. Locally, no simulation output changes observed for 10 ttbar events.
https://gitlab.cern.ch:8443/atlas/athena/-/merge_requests/67461/ needs to be merged first