Right, yeah, we've been depending on an external CDN for a long time
for jQuery and the jQuery Template library, and I don't like that kind
of external dependency! Let's put it in with the rest of our libs.
The silly motivation is that I wanted to remove `.prettierignore`,
which just exists to omit that one folder from `npm run format`. But it
also seems like this is the standard place to put them—a standard
created long after we first set this up lol
