Code a tool to update a JSON reference file

[NathanLovato]

To make the docs maker as flexible as possible, we'd like to support having JSON keys or metadata on top of the one generated by the tool. That is to say, extra fields that may not be in the tool, like code examples, links to tutorials, references... extra information that would clutter the source code.

[NathanLovato]

Note for self: better add that once we've generated the docs and actually started using the extra metadata, so we have actual data to work and test with.

[Razoric480]

Reminder for once this is implemented: the batch and/or sh tools will have to be updated in consequence as well.