convert contentnode ids to hex strings when they are stored as UUID objects in postgres
convert contentnode ids to hex strings when they are stored as UUID objects in postgres

indirectlylit/kolibri,indirectlylit/kolibri,mrpau/kolibri,indirectlylit/kolibri,learningequality/kolibri,indirectlylit/kolibri,learningequality/kolibri,learningequality/kolibri,mrpau/kolibri,mrpau/kolibri,learningequality/kolibri,mrpau/kolibri