FIDO2: support pin-less LUKS enroll/unlock

FIDO2: support pin-less LUKS enroll/unlock

Closes: https://github.com/systemd/systemd/issues/19246

Some FIDO2 devices allow the user to choose whether to use a PIN or not
and will HMAC with a different secret depending on the choice.
Some other devices (or some device-specific configuration) can instead
make it mandatory.
Allow the cryptenroll user to choose whether to use a PIN or not, but
fail immediately if it is a hard requirement.
Record the choice in the JSON-encoded LUKS header metadata so that the
right set of options can be used on unlock.