Svelte migration (WIP)

[aliabid94]

Migrating React to Svelte.

[height]

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[aliabid94]

• New frontend currently stored in "frontend-svelte".
• Subset of components implemented so far, can test with running "demo/calculator/run.py" to start backend and then running "npm run dev" from frontend/svelte-migration to launch svelte frontend.

[pngwn]

I took a quick look over this it looks good to me. I do have some questions about how we're handling the getting/setting of values, out approach to loading components, the tooling we're using here (rollup, et al), and I also have a few accessibility concerns but I don't think this is the right place for those discussions/ changes.

We should try to get this in ASAP and keep it scoped tightly to just the svelte migration and we can have those other discussions and make any improvements in future, smaller, pull requests.

[pngwn]

I think this would be more idiomatic as setValue={value => setValues(i, value)}