Improve/generate JSDocs and publish to GitHub pages

[symbioquine]

The readme for farmOS-map is already pretty long but even now there are details that aren't documented there. Publishing improving the inline documentation via JSDoc and publishing the resulting static documentation to GitHub pages would provide a way for the documentation to grow without making the readme even more unapproachable in length.

[mstenta]

+100! This will be a great next step.

publishing the resulting static documentation to GitHub pages

If we produce markdown, perhaps we should publish to https://farmos.org/development/farmos-map/ instead (like we do for https://farmos.org/development/farmos-js/ and https://farmos.org/development/farmos-py/).

I've never used JSDoc so I don't really know what's possible/what it will look like. Happy to help if I can!