[Major upgrade]: Remove webpack, use Parcel / Rollup instead

[pixelastic]

I'll need to update Webpack to v4 to v5. I'm not so happy about webpack as the configuration, albeit powerful, is hard to grasp. I'd rather have something more lightweight in the core of norska.

Alternatives are Rollup and Parcel.

What I need them to do:

• Why do I use a pug loader? Not sure, maybe not needed
• I need a custom norskaTheme resolve path to find the theme path
• I need loaders to be loaded from the norska install, not the root, so the ability to define the paths to check
• Two bundles, one for dependencies, and one for main code

Also, Webpack does not play nice with Jest. Hopefully Parcel/Rollup will work.