Make children sortable only in edit mode

The macro displaySortableChildren should let the user reorder the children only in edit mode, not in view mode. The macro should also be renamed into something like displayChildren since it is relevant to use it both in view and edit modes, not necessarily for chaning the order but just to view it. The reference parameter can be a DocumentReference or a PageReference, hence it should have a more neutral name than documentReference. A new macro displayPages could be introduced for displaying a controlled list of items.