[Joplin Server] Log origin of authentication request

[dpoulton]

@Stylbaek welcome to the forum.

The below post indicates that Joplin Server does have a rate-limiter, though that is not quite the same as Fail2Ban...

(security) Protecting joplin server exposed to the internet against bruteforce logins?

There is already a built-in rate limiter on certain actions - login and sessions in particular. This is mostly for security reasons though - to avoid DoS attack, something like Cloudflare is indeed better.