Support of MultipleSignatures would make configuration much simpler

[Kurt Fitzner]

The current method for configuring dkimpy-milter to sign with both ed25519 and RSA keys seems a little inelegant. Support for the OpenDKIM-like "MultipleSignatures" setting would simplify this significantly, removes the need for multiple KeyTable files per signing method, and should be rather trivial to implement.

As a side bonus, this support means that people can also implement the best practice of multi-key signing for the case when the mx for otherdomain.ca is handled by primarydomain.ca. It is current best practice for when primarydomain.ca servers are phyisically sending otherdomain.ca mails to have outgoing emails signed by both keys. Even when my address is <email address hidden>, if the MX that is sending the mail reverse-DNS matches to mail.primarydomain.ca, then large mailers like Google and Microsoft like to see both signatures or you tend to get into their spam folders.

Please ad this to the wish list.