In EL remapping in TC decorate with updated links instead of creating TC copies

In this MR the creation of new TC collections wiht remapped links is substituted wiht decoration of existing collections. This way the EL which are already in place (e.g. storing the seeding relation) do not need to be touched. There will be a followup in the feature access to give preference to the remapped indices (and keys). Tagging @tamartin @bwynne