Also adds a `userHandle` check for first factor verification, though this is not yet implemented in Rails controllers and UI.
This is part 1 of 3, split up of PR #23529. This PR refactors the webauthn code to support passkey authentication/registration. Passkeys aren't used yet, that is coming in PRs 2 and 3. Co-authored-by: Alan Guo Xiang Tan <gxtan1990@gmail.com>