(feat) Client Hints prototype for adaptive code serving

This is a follow-up to #38, which explores using Client Hints for adaptive code loading. Rather than just using CH for deciding whether low or high quality resources should be sent down to the client, we will use them to decide what JavaScript bundles should be served.

The idea we want to enable is the following:

- A user arrives on the site and is served an experience
- If they are on 2G/3G (ECT), a lightweight experience is served
- If they have low-memory, a lightweight experience is served
- All other users are given the "full" experience

What will differ between this example and others is that we really want to stress the difference possible between a lightweight version vs. heavy. A heavy version could include more than one component pulling in a number of different JavaScript dependencies.

Let's brainstorm what the best demo for this should be.