Show info about the existing crawler workflows.

def list_crawler_workflows(tail):
    """Show info about the existing crawler workflows."""
    query = (
        models.CrawlerWorkflowObject.query
        .order_by(models.CrawlerWorkflowObject.object_id.desc())
    )
    if tail != 0:
        query = query.limit(tail)

    workflows = query.yield_per(10).all()
    _show_table(results=workflows)