primer-service: look into RFC 9457

[dhess]

Ref:

• https://datatracker.ietf.org/doc/html/rfc9457

[dhess]

This is pretty low priority, as it's not clear whether primer-service has much of a future, now that we've had some preliminary success re-implementing the Primer UI in Haskell via Miso and Wasm.

It's possible we'll still have a backend of some kind, but it would likely be much different than the current implementation, and focus primarily on managing storage/databases for collaboration in classrooms and the like.