Migrate build/local serving to Vite

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Our current Rollup/Gulp combination is slow, cumbersome, and less likely to give us the optimized output we'd want than Vite is, which is optimized for code splitting and modern ES module forward builds.

• Migrate site serving from Rollup/Gulp/BrowserSync to Vite and Eleventy and ensure Eleventy compiling still works
• Ensure JS works in dev
• Ensure Sass works in dev
  • Filed issue that we're currently having
  • Filed PR to help debug error I'm getting
• Ensure JS compiles for production
  • Regular JS works as expected
  • Workers work as expected
  • Service Worker works
• Ensure Sass compiles for production
• Ensure dynamic import polyfill is included (if not already)
• Make sure Firebase proxies for functions run during dev.
• Ensure Search indexes compile

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Got unblocked on Sass, turns out Squoosh was affecting how Sass gets imported by Vite. Removing Vite Plugin Img made Sass work again!

This means that, for #154, Squoosh will need to be removed as a render option from Vite Plugin Img if we wind up using that module.

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Need some of the transforms from #143 complete in order to finish this (otherwise required hooks for JS and CSS may not be there!). Kind of a circular dependency situation; needed the 1st half of this to be done to then start on that to then finish this.

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Compiling of HTML is blocked on vitejs/vite#6113

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The PR got merged and I've got a patch that we can apply locally to unblock this for now until the PR lands in a stable branch

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Featured paint worklet is a little funky but otherwise it looks like our JS, workers, and service worker work as expected.

Filed vite-pwa/vite-plugin-pwa#192 so we don't have to precache all of the HTML

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Upped to a 21 because this actually was more like a mini epic

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With 2a18001 I'm marking this issue closed. The site runs great in both dev and prod builds using the new setup. The service worker still needs work, but we knew that already. Any additional bugs will be filed and worked on independently.