* Load script here in order to get window.opener.location.host
* Send back to server: wiki adress + session_id: https://deadlinkchecker.toolforge.org/finishlogin?wiki={wiki_address}&sessionid={session_id}
* Saves on database: UPDATE users SET language = $wiki WHERE session_id = $session_id
* Redirects user to Special:Deadlinkchecker