Feature/3 scenario setup

[davemfish]

This PR builds the scenario-creation form around the API designed in #2 . There's a fake backend here now in scenario.js, which uses the browser for storage. But that will be completely replaced, and then the calls in requests.js can be updated. I think the set of functions in requests.js will stay, but the body of each one will be rewritten against the real backend.

The functionality includes:

• Creating a new scenario or adding to an existing one
• Making a wallpapering request, assigning the job to a scenario, and getting back results
• Exploring existing scenarios through a summary table. So far the data in the table is missing, but rows get updated when new scenarios are created.

I tried out Blueprint for basic react components. No complaints so far, but I also don't think we're locked in to that if we want to continue trying other libraries. I briefly considered Carbon but shied away from it when I saw it requires configuring a SASS build. That's probably not a big deal, it's just one more new thing I didn't want to get stuck on right now.

I also added a basic eslintrc.js which we can continue to modify with our preferences.

[emlys]

I'm getting a warning in the console when I first load the page:

Warning: Each child in a list should have a unique "key" prop.

Check the render method of `ScenarioTable`. See https://reactjs.org/link/warning-keys for more information.
td
ScenarioTable@http://localhost:3000/src/scenarioTable.jsx:24:7
div
div
Tabs2@http://localhost:3000/node_modules/.vite/deps/@blueprintjs_core.js?v=7f24dc36:17831:24
div
EditMenu@http://localhost:3000/src/edit.jsx:31:7
div
div
App@http://localhost:3000/src/App.jsx:23:55

[davemfish]

Okay I removed the popup code. And I addressed the warning about missing keys. Thanks!