Error during postprocessing (specifically, metadata-file generation) ignores shutdown.txt and fails to remove incomplete metadata-arc file

When an error occurs during metadatafile generation, the whole job is moved to the oldjobs folder, and a new job is started subsequently - also when a shutdown.txt is present in the main folder of the harvestercontroller.

This gives us the risk of uploading incomplete or corrupt metadata warcfiles when executing the upload_failed_warcs.sh script

Instead it should close down the harvester and send one or more notifications: One that errors were encountered durign metadatageneration, two: That the harvester were shutdown at this time and date