refactor: Migrate from Next.js to pure webpack config (#360)

Fix for #348 - migrate our NextJS project to a pure webpack project w/ a single bundle

- [x] Switch from `next/link` to `react-router-dom`'s link 

> This part was easy - just change the import to `import { Link } from "react-router-dom"` and `<Link href={...} />` to `<Link to={...} />`

- [x] Switch from `next/router` to `react-router-dom`'s paradigms (`useNavigation`, `useLocation`, and `useParams`)

> `router.push` can be converted to `navigate(...)` (provided by the `useNavigate` hook)
> `router.replace` can be converted `navigate(..., {replace: true})` 
>  Query parameters (`const { query } = useRouter`) can be converted to `const query = useParams()`)

- [x] Implement client-side routing with `react-router-dom`

> Parameterized routes in NextJS like `projects/[organization]/[project]` would look like:
> ```
>               <Route path="projects">
>                    <Route path=":organization/:project">
>                    <Route index element={<ProjectPage />} />
>                  </Route>
>               </Route>
> ```

I've hooked up a `build:analyze` command that spins up a server to show the bundle size:
<img width="1303" alt="image" src="https://user-images.githubusercontent.com/88213859/157496889-87c5fdcd-fad1-4f2e-b7b6-437aebf99641.png">

The bundle looks OK, but there are some opportunities for improvement - the heavy-weight dependencies, like React, ReactDOM, Material-UI, and lodash could be brought in via a CDN: https://stackoverflow.com/questions/50645796/how-to-import-reactjs-material-ui-using-a-cdn-through-webpacks-externals

.github/workflows/coder.yaml

@@ -352,6 +352,8 @@ jobs:
         working-directory: site
 
       - run: yarn playwright:test
+        env:
+          DEBUG: pw:api
         working-directory: site
 
       - name: Upload DataDog Trace