Fix METMap for PHYS -> PHYSLITE production

The MissingETAssociationMap (METmap) is the main blocker for being able to produce PHYSLITE directly from PHYS at the moment - the METmap exists in PHYS, but cannot be directly copied for use in PHYSLITE as PHYSLITE contains calibrated objects, so the existing element links in the map will be invalid.

The proposed solution is to add a new algorithm to produce a corrected METmap by relinking the ElementLinks contained in the map to calibrated objects as appropriate.