The nginx-to-uwsig-timeout defaults to 60s, which is exactly the same
as the current "harakiri" timeout configured in uwsgi (which limits
the length a request can run before the worker is terminated). This
causes a race, where if nginx hits its 60s before uwsgi, then we
return a 504; otherwise, we get a 502.
Make the nginx-to-uwsgi timeout explicit, and shorten the "harakiri"
timeout to be explicitly less than that. Document the 60s timeout,
which all outer reverse proxies must be set to _longer than_ in order
to have proper "onion" timeouts.
- Makes "Deployment options" easier to navigate by splitting the
"Reverse proxies" and "System configuration" sections out into
dedicated pages.
Fixes#28928.