This will improve:

• swh-loader*: a posteriori analysis for loading failures (no longer need to query on the task's arguments which completely depends on the loader's nature)
• webapp: the save code now where we could provide more information on the status' visits (at the moment, nothing is provided)
• swh-indexer: that could also help in the metadata indexers to check for the visit's status (which could also be implemented in other ways but hey ;)

This calls for:

• sql:
  • add a new column origin_id on table task (not null)
  • add new columns origin_id, visit_id on table task_run (not null for both)
  • create independent indexes on those new columns
• loader-core: update the load_status method to provide the origin_id and visit_id as results (alongside the current eventful/uneventful status)
• lister: update them so that when scheduling a task, we provide the origin_id (T1471 could ease that step :)
• migration: After schema migration, we need a routine that actually fill in the gaps in existing task/task_run.