RetinaCluster v1

Introducing a slightly modified version of the mdf_for_standalone_Allen.py script to account for the RetinaClustering algorithm.
The PrTrackerDumper call within mc_checking.py has been changed to account for different VELO clustering algorithms.
hlt1_reco_decode_retina_with_mcchecking_FTv6.qmt and hlt2_reco_decode_retina_with_mcchecking.qmt tests added to decode RetinaClusters from input files instead of reconstructing clusters from SPs.

Dependencies

This MR is part of a 6-MRs package, including LHCb!3385 (merged) (main MR), Allen!748 (merged), Rec!2695 (merged), Detector!165 (merged) and lhcb-datapkg/PRConfig!227 (merged).