With !19 we currently only support OpenPGP certificates with a single [component key](https://openpgp.dev/book/certificates.html#component-keys). This is usually enough for our signing setup, but in the future it would be great to be able to support OpenPGP certificates with multiple component keys. A setup like that requires us to assign multiple NetHSM keys to the use of an OpenPGP certificate and encode the key IDs of the component keys in the certificate.