use correct entity log function
made celery_tasks accept wider variety of task result content

Instead of crashing on anything that was not an entity or file URL
accept collection URLs, and just pass through if not a URL at all.
include traceback in celery task if present
catch missing field errors when formatting celery tasks

When I've seen an error at this point the task has already had
a message.  This change tries to use that message if it's present
and uses the raw template if not.  That way at least the user
has some idea what error was being reported.