Create a referrer that has no Greenhouse user account, such as an outside referrer, so applications can be credited to them. Pass the returned id as referrer_id when creating or updating an application. name is matched case-insensitively against the organization's existing outside referrers (those not linked to a user, agency recruiter, or LinkedIn recruiter); when a match exists, that referrer is returned with a 200 instead of creating a duplicate. Requires the user to be able to manage the organization's custom options.