Reference files with xAOD classes generated by q-tests
Reference text files with lists of containers stored in AOD files from q-tests (after !45986 (merged)). A MR for the CI will follow to give a warning if the AOD container content changes from the reference, as discussed in software coordination (attn @elmsheus , @emoyse ).
Could also go in 22.0-mc20, I leave it to RC discretion.