Yet another favicon revamp

[carstene1ns]

• Windows Metro/IE icons and Apple touch bar icons can be removed, both are dead¹
• SVG icon should be added, replaces almost all other PNG resolutions, introduced in 2017
• 96x96 desktop PNG icon should be added, as "high-res" fallback, debatable if we also remove lower res fallbacks then

This reduces the images over 50% and gets rid of an unused manifest xml and 6 meta tags (half a kb! :D) each page. (current config for reference: e1731aa)

Footnotes

1. https://realfavicongenerator.net/blog/windows-metro-and-macbook-touch-bar-icons-discontinued ↩