Web IDL in documentation is not compliant Web IDL

[kenchris]

Multiple different mistakes, like using types like "string" which doesn't exist in Web IDL:

https://heycam.github.io/webidl/#prod-StringType

[zolkis]

Perhaps we should stop using WebIDL in zephyr.js (unlike in browser development, we don't take much benefits from using it), and use e.g. TypeScript, or plain JS for describing interfaces (like here)?

[grgustaf]

Our plan had been to move to Node-like documentation as I started on with Buffer. But then PR #1800 came in and there seemed to be interest in retaining WebIDL. Since that has stalled, we should probably resume the Node-like conversion.