Serialize all D-Bus fields and enum values with snake case #82
Description
We borrow a lot of fields and values from WebAuthn. For internal consistency and consistency with other D-Bus APIs, I think we should convert them to snake_case instead of camelCase, as is more common in JavaScript.
This includes the publicKey field of create/get credential requests, topOrigin (#81), etc.
This is a breaking change to the API.