Externalizing/unbundling resources

Various resources (fonts, js, css) are embedded into the mdbook executable, and bundled into built books. This is probably sometimes unwanted.

Can we find a way to externalize/unbundle these? For example, let the built books reference fonts in a Debian package.

Problem 1: There's no way to specify Debian packages to install for a built book - it's not a .deb. It's probably not even served on a Debian server.

Problem 2: We don't know how the book is supposed to be served, so there is no knowing in advance in what form to reference the resources. A symlinked directory alongside index.html? Absolute path?

This is probably not our fight. But it doesn't hurt to discuss.