Introduced xAOD::EventAuxInfo_v3 as a copy of xAOD::EventAuxInfo_v2, with the beam-spot variables removed. So that they could be handled as decorations from now on.
Updated the POOL converter package to introduce T/P converters implementing the schema evolution to the new _v3 type.
I was meaning to introduce a specific test in xAODEventInfoAthenaPool for the v2 -> v3 test, but couldn't find any release 22 reference AODs under /cvmfs/atlas-nightlies.cern.ch/repo/data/data-art/aod.
This is meant to be the first step in solving ATLASRECTS-6707. The algorithmic code for filling the beam-spot information shall come in follow-up MRs.
Note: In the end an algorithm (xAODMaker::EventInfoBeamSpotDecoratorAlg) was added into this MR already for filling the beamspot information correctly in data reconstruction jobs.