Added AOD2xAOD Truth conversion in RecoSteering sequence for CA-based config
This MR introduces in the CA-based RecoSteering config the xAODTruthCnvAlg used to create the TruthEventContainer, TruthVertexContainer and TruthParticleContainer.
The case of the full-PU truth is handled based on the digiSteeringConf retrieved from the metadata as in https://gitlab.cern.ch/atlas/athena/-/blob/master/Event/xAOD/xAODTruthCnv/python/xAODTruthCnvConfig.py#L9
However, the digiSteeringConf does not appear to be saved yet in the metadata, so in case there are other suggestions, I'm happy to try something else.