Move documentation to a Jekyll site

[rossjrw]

Instead of wasting time documenting the changes I'm making in #6 in either the current format or a new temporary one, I may as well take this opportunity to move everything to a Jekyll site.

• [ ] Move main docs to a Jekyll site
• [ ] Change build and preview processes to be for this site
• [ ] Create an equivalent of #1 (or rebase it) to preview changes for this site
• [ ] Use includes for the yml files while still keeping them as independent files

Merges into #6.

(edit: just in case anyone is wondering why this PR has been open so long, I did a whole lot of work on this and then that computer got wiped in an unrelated incident. push regularly!)

[github-actions[bot]]

PR Preview Action v1.1.1 :---: :rocket: Deployed preview to https://rossjrw.github.io/pr-preview-action/pr-preview/pr-8/ on branch gh-pages at 2022-04-18 06:37 UTC