Redesign website (#2628)

* Bump up Bootstrap to v5.3.1, Bootstrap Icon to v1.10.5.
* Use autoComplete.js to drop dependency on jQuery and typeahead.js.
* Support dark mode.
* New svg logo and icon with responsive color mode support.
* Normalize section ids to lower kebab-case for easiness of linking.
* Use relative paths for links for local development (--root /output).
* Various markup cleanups and accessibility improvements.

.github/workflows/website.yml

@@ -20,7 +20,7 @@ jobs:
       - name: Setup Python
         uses: actions/setup-python@v4
         with:
-          python-version: '3.10'
+          python-version: '3.11'
           cache: pipenv
       - name: Install pipenv
         run: pip install pipenv