Move guide on how to write stories from Google doc and instead publish on IDG.community

[Greenheart]

Now that the content has stabilized, we could remove the dependency on Google docs and publish it on our website instead.

This will be a much better UX when everything is in the same context.

If we publish it as a big markdown page, it could also be updated pretty easily via the CMS. We could add a new collection for pages or something like that. Or some other solution.