goat: generic record data

[bnewbold]

Little hack to make goat work better with generic record data, aka when we don't know the Lexicon. In this context, just dumping the JSON to stdout (pretty printed).

Sharing b/c we might want to do this generally, at least for API endpoints: json.RawMessage instead of lexutil.LexiconTypeDecoder when we encounter unknown schema type. Note that this won't work for records, and the schema rules do allow unknown in records, it just hasn't happened yet.

Another place we encounter this is DID documents, which don't even have $type in the JSON.