Parsing to JSON schema

[Tommaso-Pincelli]

It would be useful to parse the hierarchy of NeXus files into a JSON schema. This might be useful for easier human readability and editing.
It might also help to facilitate interoperability and harmonization with other schemas, such as the one being drafted by Dr. Greiner for XPS (https://github.com/mgreiner79/xps_json_schema).