Generate and render list of implemented languages as a web page

[mtso]

• Write a procedure that creates a list of hof-implementing languages
• Write a procedure that renders a web page from the list
• Add a ci step that runs the procedures and publishes them to gh-pages

[mtso]

An alternative could be a list_langs procedure that overwrites README.md like https://github.com/leachim6/hello-world/blob/master/CONTRIBUTING.md