add ability to check whether a mediapackage has been published before trying reingest

this lets you choose to make galicaster check matterhorn to see if any media package which says the ingest has failed according to galicaster has actually previously succeeded. if it is found to have already been published in matterhorn, the status is updated to say the ingest has succeeded and it is not re-ingested.

not sure how useful this is to anyone else, but it helps us get rid of some duplicate processing where testing has left the ingest state as failed even though it has previously succeeded.