More idiomatic JSON

[JDziurlaj]

Right now the JSON schemas developed produce JSON that somewhat verbose. In large JSON files, it's clear this is coming from two areas:

1. @type key is always required, even when it can be inferred
2. InternationalizedText typed properties use an overly complicated structure

The solution to (1) might be to allow this key to be omitted when the usage is clear (e.g. when the object's type does not have subtypes). For (2), we could look at the structure in JSON-LD for RDF language tags.