WIP: JetMET: UFO Reconstruction migration to flow elements
This first merge request (in series) will update the UFO reconstruction code to use FlowElements by default instead of PFOs.
NB: This is not executable yet - only inclusions in this MR will be the update of container handles etc to xAOD::FlowElement from xAOD::PFO and how to read tracks/clusters/auxvars from the FlowElements. So this works at compile time, but the algorithm is not fully migrated.
PS: will update the TrackCaloClusterConfig.py in a more "neat" way since this is still very much work in progress - a full configuration will go into a subsequent MR Perhaps we might want to move the TCCHelpers struct (and their dependencies) into a class with inheriting pieces perhaps? I might also clean up this branch to only include the relevant changes here since this might be wrapped up with some changes currently in another open MR.