Add a task to queue cleanup of images that have been updated for postage stamp requests.
It runs twice a day and discovers whether or not there are any unfinished postage stamp
dependents. If not queues all of the chip, warp, and diff runs in gpc1 database with label like ps_ud%
to be cleaned. If there are outstanding dependents it does not queue the updates since we don't
want to cause problems with the postage stamp jobs that are depending on them.
This should be much better than the formerly manual process which got done whenever Bill happened to think of it.