Add topo cluster moments to photons as decorations in EGAM3 and EGAM4
This MR adds as decorations of the photons in EGAM3 and EGAM4 the topo cluster moments, for photon ID studies, as discussed in this JIRA ticket: https://its.cern.ch/jira/browse/ATLEGAMDPD-140
Tested successfully on MC and DATA AODs
Edited by Giovanni Marchiori