Tweak the way the Yaga rule interface and the Yaga super class are loaded

The Yaga rule interface as well as the static super class can be auto-magically brought into scope using Garden's autoloader instead of being manullay included where needed.

I also renamed `lib` to `library` as this is used everywhere else in Vanilla and moved the rules into the `library` dir to keep everything in the same place.

Lastly, I made `about.php` a little more readable – my imaginary OCD took over for a minute :smile: