Pure static version, for gh-pages (no back-end / API)

I developed this version because:

• Glitch.com was sometimes not responding => causing latency on Trello's power-ups page
• Some stranger gained access to the Glitch's code => broke the power-up in production!

Now that the power-up is hosted by Github Pages, and associated to my personal domain name (with HTTPS/SSL and CDN caching kindly provided by Cloudflare), it should be faster and more reliable.