Replaces Webpack 4 with latest Vite

[aendra-rininsland]

This is a very substantial change but hopefully it will fix a lot of annoying fiddly issues moving forward.

Pre-merge checklist

• [x] Ensure that HMR is working properly. I don't think it does ATM.
• [x] Comments seem to be broken for some reason
• [x] Build is failing for some reason