Paginate signatories list

[craigcook]

The list is already unwieldy at only 377 at time of writing, but there are a lot more in the queue pending verification and more to come. It's a long scrolling list that will only get longer, and it's also adding a lot to the page weight. We need to make a better way to display signatories, probably paginated with maybe 100-200 names per page.

Related, we also need a less labor-intensive means of formatting signatories. They're all hard-coded right now but we do have them in a JSON format that we can parse and transform any number of ways. This could be done server-side at build time, maybe rendering separate pages with proper URLs, or client-side with some ajaxy stuff to fetch chunks of the list. If we go the client-side route I'd still like some kind of non-JS static fallback, even if it's just one giant page of all the names in a tiny font.