Retries log as failures

Description

This MR changes retries to be logged as failures as expected. This also addresses a bug (#619 (closed)) found during the implementation of this MR.

Changes proposed in this merge request:

• Log retries as failures
• Require message.logfile to be set prior to attempting to read the last 20 lines
• Unhandled exceptions during jobs now cause permanent failure as opposed to temporary.

#616 (closed) is addressed as retries have changed from WARNING to FAILURE. However this is not enough to close the issue as it requires further work towards #456 (closed) (started in !670 (closed))

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