Integrate the cbor-x library again

we copied the code to make it work in React Native. But now that metro has a new unstable package exports feature i think we can make it work in React Native without modifications to the package.json. This way we get the benefits of updates to cbor-x and are able to remove some code from this library


https://metrobundler.dev/docs/configuration/#unstable_enablepackageexports-experimental

