Create documentation & add to tool

[changesbyjames]

I'm really keen for this to be a tool that goes beyond what it was designed for and for it to be a useful and stable home for this data. For that, the best thing to do is be as open as possible.

Part of that is putting work into integration options and exporting but a huge part of that is documentation.

Let's not over complicate things, let's do a markdown based /docs folder that we can edit and publish through GitHub and then have those docs be discoverable through the tool. (Maybe displayed inline)

• Add directory & menu.json
• Render in the tool
• Add link to the documentation
• Add "Edit in GitHub" links