Maintain and serve a PGXN web site

Changes for 0.23.6 - 2024-02-20T20:56:52Z

• Tweaked the indentation of list items in the documentation "Contents" nav box to align with the text above.
• Fixed broken SVG images. Turns out browsers don't know that `https://www.w3.org/2000/svg` is valid. Reverting them to `http://www.w3.org/2000/svg` fixes the issue.
• Regenerated all the logo images. Most are a bit smaller now, and some superfluous data was removed from a few others.