Automatically prompt FIDO Login on login page launch

[tomy0000000]

Summary

The current flow of login with FIDO is to click the FIDO login button, authenticate, then login. Some website (e.g. PayPal) prompt for FIDO without asking, which is more fluent and faster.

Motivation

It's way faster to log in if this is implemented.

Additional context

Some users that are not using FIDO login may find this disturbing, so another consideration would be make a switch to decide if Mailcow should behave so.

If this is something you'd like to see, I can try working on this and submit PR.