Update browser <-> server API to reflect upcoming JSON serializers in WebAuthn L3

[MasterKale]

The Chromium team is beginning to prototype the new JSON serializers I got into L3 of the WebAuthn spec 🎉

https://groups.google.com/a/chromium.org/g/blink-dev/c/ePTIazJJ2TA/m/Bw6fwg1AAgAJ

Now's a good time to update the types in this project to mirror the types defined in the spec, so that one day a developer could use native WebAuthn API calls with @simplewebauthn/server, if they didn't also want to use @simplewebauthn/browser.

References

• https://w3c.github.io/webauthn/#typedefdef-publickeycredentialjson
• https://w3c.github.io/webauthn/#sctn-parseCreationOptionsFromJSON
• https://w3c.github.io/webauthn/#sctn-parseRequestOptionsFromJSON

[MasterKale]

#320 has been merged so this'll debut when v7.0.0 is released