AdashimaaTube: Restore old YouTube layout with many customizable options

Wow, this is great! While notable YouTube regressions like pushing Shorts are obvious, even I was surprised by how subtle the creeping enshittification over time has been. They just slowly take away one little useful thing after another.

While this script is awesome, it's sad that users who care about utility now have to play endless Whac-a-mole with websites and even browsers (I have to run a mountain of custom CSS to keep Firefox usable and useful against Mozilla's constant changes).