SSH public key login
Related to https://github.com/freedombox/freedombox-todos/issues/11, allow the user to upload their public RSA key and add it to the SSH authorized keys, so they can use SSH without a password.
Related to https://github.com/freedombox/freedombox-todos/issues/11, allow the user to upload their public RSA key and add it to the SSH authorized keys, so they can use SSH without a password.