Prebuild Frontend

[matthew-white]

It's taking increasingly long to build Frontend. It'd be nice if we could ship built Frontend assets rather than requiring users to build Frontend. We just discussed a specific approach to this:

• 1. Rather than include the Frontend config in the Frontend bundle, send a request for the config when Frontend is loaded.
• 2. Serve the Frontend config from nginx. We could template it in a similar way as we do the Backend config.
• 3. Build Frontend automatically.

I'm going to work on (1) and (2), and @lognaturel is going to take a look at (3).