Allow authorized_keys options

Proposal

GitLab expects new SSH keys with the format keytype, base64-encoded key, comment.

However, sshd(8)#AUTHORIZED_KEYS_FILE_FORMAT allows additional options, like verify-required and no-touch-required in the format: options, keytype, base64-encoded key, comment (with options being optional).

The option no-touch-required is required for FIDO2/U2F keys generated with the option no-touch-required to not require a touch verification on each SSH authentication and therefore my key always get declined by GitLab without that option.

It would be very nice to allow prepend the option in the SSH add form (https://codeberg.org/user/settings/keys).

For example this is a line in my authorized_keys for my machines:

no-touch-required sk-ssh-ed25519@openssh.com AAAAGnNrLXNzaC1lZDI1NTE5QG9wZW5zc2guY29tAAAAIIqB47mxdo+mLFKxncPu8fA6jrKeVrBwCQ1Hoylr1n7kAAAAC3NzaDpnZW5lcmFs nk3

I think setting no-touch-required by default would be wrong and is a potential security risk.