Add a script to replace obfuscated css class names with real ones that are exported in js files

[Lifeismana]

test run of it: https://github.com/Lifeismana/SteamTracking/commit/d635ae5e33825d89b6371df586890f3deb8736c2

Don't have an easy way to estimate how much of an impact it will have on run time, full run is 23sec on a 9800X3D giving it a single css file makes it less than 5 seconds which makes it negligible although it might be better to just detect if a css file was updated and if so do a full run (I think i'm also missing a bit of code to make it run when there's new steam client files)