Add simple markdown docs

Hi, fellow hackathon-ers! The Toolforge docs group is working on the prototype for docs.toolforge.org, and we're looking for a repository to include as an example. Even though Autosuggest Linking Wikidata is a work in progress, I thought it would be fun to use it as our example. This would mean adding a basic markdown doc to this repo and registering the repo with Toolhub. Let me know if you have any questions!