Move html5boilerplate website to this repo and expand it (have the docs online)

As discussed on a call yesterday with @roblarsen - I think it'd make sense to move the html5boilerplate.com website to this repo. This could mean:

• The docs for the repo (currently markdown files) can be easily viewed on the website (with a edit this page link at bottom for contributions).
• We could move the single page of the wiki (Project history) to the site too.
• We have a list of H5BP projects at https://h5bp.org/ - we could move that over too (and redirect the domain).

There are a number of options of how to build this newly expanded html5boilerplate site, I suggest we keep it as simple and lightweight as possible, but it would require a markdown to HTML convert step at build time.

Overall, I think either building and designing thee site ourselves with Astro building it might be a good fit, but Astro Starlight could be a good option too. I use Starlight for the HTMLHint website and it looks good, is very fast, easy-to-maintain. But open to other suggestions.