Change to automatic color generation

[xavimiranda]

By using the sass pre compiler, this commit turns the original css rules into a function, that can be called with only the datapath and the color arguments to generate multiple css rules

Hello @CyanVoxel, I'm not really expecting this to be merged, but hopefully it conveys my vision of the potential your original project. I also overridden the readme to explain things a bit further, which would need to be fixed in case you actually want to use any of the changes.

I was inspired by your 2024 vault tour, and wanted to make the Colored Sidebar work for my PKS :)