Switch to a more standard codebase and build pipeline

[netux]

The current way files are split is very developer unfriendly, as we get basically no IntelliSense. Debugging is okayish because of demo.html and DevTools, but it could be better.

Consider linking all files through module imports/exports, and building with standard tools like Parcel/Rollup/Snowpack/esbuild.

[CactusPuppy]

If I ever get enough time to dedicate to this, I would love to tackle it. It's quite an overhaul at the moment though.

[CactusPuppy]

This can't happen soon enough.

[CactusPuppy]

Closed in #366