[Feature] Add 2FA to Admin Authentication

[gondolyr]

It would be a good security addition to add 2FA as an option, particularly WebAuthn, so that we can use security keys such as the YubiKey or Nitrokey. It would help mitigate attack methods, such as brute-force, from attackers accessing the admin settings. As far as I can tell, the username cannot be changed from "admin" so an attacker would probably only need to start guessing the password.

Resources:

• https://fidoalliance.org/fido2-2/fido2-web-authentication-webauthn/

[gabek]

This is unlikely to be anything that I work on in the near future, but I'll keep this open in case somebody would be interested in looking into it.