Add Controller Document examples to the Data Model section

[selfissued]

This issue replaces an issue described within the specification itself at https://www.w3.org/TR/2024/WD-controller-document-20240817/#data-model.

This is part of addressing #52.

[selfissued]

I agree that this is ready for a PR. Ideally, there should be an example not using JSON-LD and another example using it.