added delete button in event registrations table
added delete button in event registrations table

silverstripe-australia/silverstripe-eventmanagement,burnbright/silverstripe-eventmanagement,stephenmcm/silverstripe-eventmanagement,registripe/registripe-core,silverstripe-australia/silverstripe-eventmanagement,souldigital/silverstripe-eventmanagement,stephenmcm/silverstripe-eventmanagement,souldigital/silverstripe-eventmanagement,burnbright/silverstripe-eventmanagement