WIP: Prototype of UI component catalog/design system with elm-ui-explorer

[hagl]

Overview

I've set up elm-ui-explorer for the project and added a few stories for Button, Tooltip and Modal.

The UI Explorer can be started with npm run uie and is then available on http://localhost:1235

Adding static components is straightforward, but adding interactive components seems rather cumbersome since the model and update function are global for all components.
One example where some interactivity is necessary is the Modal story: Simply rendering the modal component statically (as it is done now) makes the UI unusable because the modal dialog cannot be closed.

So in all, I'm not completely convinced this will add enough value. But since I spend some time getting it running, I created the PR as a basis for discussion.

Implementation notes

I use webpack to run the UI Explorer instead of elm-live that comes with elm-ui-explorer to reduce the number of new dependencies. I kept the webpack configuration very similar to webpack.dev.js

Loose ends

The changes in package-lock.json seem massive, it might be worth investigating if we want to continue with this PR

[hojberg]

Cool! Yeah that is a lot of new dependencies, but it does look pretty cool 🤔