Restructure and remove Jekyll site folder completely

[BenJetson]

Sub-tasks:

• Fix Vercel builds so that they use the repo root.
• Ensure CMS system configuration now uses repo root.

Note that this happens separately from the final deployment. This is an action that can happen in later development phases at a point where the old Jekyll site code is no longer considered to be useful.

These changes should only impact the develop branch at the time, and GitHub Pages / Netlify will continue working normally off of master until final deployment later.