Retrying a queue item means cloning it, resetting all execution-related state. Retried queue items reference the item they were retried from by id. This relationship is not enforced by any DB constraints.
- Add `retried_from_item_id` to `session_queue` table in DB in a migration.
- Add `retry_items_by_id` method to session queue service. Accepts a list of queue item IDs and clones them (minus execution state). Returns a list of retried items. Items that are not in a canceled or failed state are skipped.
- Add `retry_items_by_id` HTTP endpoint that maps 1-to-1 to the queue service method.
- Add `queue_items_retried` event, which includes the list of retried items.