TDR code, aka code that would break master but is needed to run TDR tests

This should NOT be merged as is in master as it contains code that is not at the quality level needed for that. When the time of the merge will come, the part concerning VPLightClusters has to be extracted and merged to master while the rest stays here

Concerning the breaking, it is mainly in the MC linking. This code needs some merge requests from Gaudi to be included, namely gaudi/Gaudi!536 (merged), gaudi/Gaudi!537 (merged), gaudi/Gaudi!538 (merged) and gaudi/Gaudi!571 (merged)