To optimize rarely used but potentially useful resources:
- User asks a resource reaching https://quux.nasqueron.org
- Nginx tries two upstream target; the app, then the app launcher
- If the app is up, okay, serve it
- If the app is down, we're in the launcher, which autostart the container (or ask user confirmation to do it), then redirects to the launched app
Some special URLs like /alive /status shouldn't trigger the launcher.