put nginx in the same container as the application

[mgeplf]

• everything runs under supervisord; this allows for easier debugging, save us an EFS volume, and enable better caching in a forthcoming commit

[kplatis]

Probably unrelated but I run a stress test locally with 20 VU, without using the cache and the results are the following:

• CPU maxes out
• Memory not getting released

[mgeplf]

Cool, let's do that in another ticket: if you say how you did the setup, that should make it easy to track down.