Add overview page from v0

[szhu]

This adds the overview page over from v1!

@macfarlandian please read these important notes:

• You can visit the page by running bin/parcel serve index.html and going to http://localhost:1234/overview
  • You can instead run yarn dev after Add form page and development scripts #3 is merged!
  • I just picked /overview, but I can change the URL if you have an opinion.
  • Once you're there, the page looks exactly the same as before!
    
• Here's where your files have gone:
  • src/index.html -> src/page-overview/OverviewPage.tsx
  • src/style.css -> Also src/page-overview/OverviewPage.tsx! (Check the top of the file)
  • The tailwind built-in styles -> src/page-overview/assets/output.css_
  • src/*.js -> src/page-overview/assets/*.js_ (the nonstandard file extension tells Parcel to not preprocess the file)
  • src/icons/* -> src/page-overview/assets/icons/*
• Normally, in development mode, the page will instantly update, without even reloading, as soon as you save a file. Because the current JS isn't aware of the React rendering lifecycle, you'll instead get a blank page. Just reload the page to see your updates for now.
• To build the page for deployment, just run yarn build as usual. I tested it and I think it works perfectly.

Things that are hacky that we should eventually migrate off of:

• [Really hacky] Since we use react-router, we should migrate the JS to (1) not use global variables update: this is done! and (2) to be aware of the React lifecycle. Note: Currently your v0 overview page JS is run on all pages, not just the overview page!
• [Really hacky] We currently have two style systems (the styles imported from v0 by this PR and the styles added in Add global styles + base for form page #2) that might clash with each other. We should take a look at that. (Note: I am investigating this in a larger scale, having a conversation with Juan about what the design system of this website will be.)
• [Not a big deal] We should migrate the JS to be proper React code.
• [Not a big deal] There's a really big SVG included in the the HTML. Nothing's technically wrong, but we should move the SVG into another file and import it.

[macfarlandian]

@szhu given that output.css is a generated file, is it necessary to track it?

[szhu]

@macfarlandian Hmm… it looks like we can just use a pre-compiled version.

Thanks! This PR's diff is way smaller now!

[macfarlandian]

seems mostly fine ... a few minor things broke but they are all things I am going to change anyway so I think this is good to merge! Thanks for taking care of this

[szhu]

@macfarlandian the js files are fixed! They are now complied through the Parcel pipeline rather than included verbatim. Saving JS files should no longer cause errors, but note that since they are still not aware of the React lifecycle, you'll need to reload the page to see most updates.