Add purge unprocessed jobs

I've updated the patch and added a hook_update_n to set the default value to '_never'.
To keep settings consistent with purge_finished settings, we should not use 0 here, because this is used as immediatly value there.

Adding accessCheck to prevent Drupal\Core\Entity\Query\QueryException: Entity queries must explicitly set whether the query should be access checked or not. on cron run.

The last submitted patch, 9: Add-purge-unprocessed-jobs-3089363-9.patch, failed testing. View results →

tmgmt_update_8011 was already declared, bumping to tmgmt_update_8012