Draft: start work on the docs newbie guide

This merge request is for the "getting starting writing guides" guide.

This guide should teach people new to writing guides the steps that are recommended for doing so. It's largely based on the approach I've been using for the guides on the site and tutorials I've written over the years. If I've missed something out or there is a better way happy to make changes.

It's a bit of a braindump at the moment. I'll clean it up in the next phase before sending it out :).