Allow importing from arbitrary npm packages for better demos

[NullVoxPopuli]

I had wanted to use Limber for showcasing https://github.com/NullVoxPopuli/ember-statechart-component/, because the story here is really slick with template imports -- but xstate (and ember-statechart-component) are not included in the Limber build.

It'd be great if you could import from 'x' and have x added to your page at runtime, kinda like what https://runkit.com/ does for node packages

How this might look (but with gjs live instead of just gjs)

[NullVoxPopuli]

example:
this should be able to work: import { toBlob } from 'html-to-image'
Also, importing components from from the app should be doable as well

[NullVoxPopuli]

In case browsers don't support script[type=module] properly, or import maps: https://github.com/guybedford/es-module-shims

For re-writing imports in scripts without jscodeshift or silly regex: https://github.com/guybedford/es-module-lexer

Example of dynamic updating of the import-map: https://github.com/huozhi/devjar/blob/main/lib/module.js

[NullVoxPopuli]

Allowing service worker composition: https://mswjs.io/docs/recipes/merging-service-workers/