Set the nginx timeout value

[decko]

When users want to change the gunicorn timeout, they can set the PULP_GUNICORN_TIMEOUT to a value of its choice.
But this only works when you set it to a value less than 60 seconds. After that, the application doesn't increase its timeout.

The reason is that we need to set the same value to nginx itself, since it's a proxy between gunicorn and the client.

[stbergmann]

(What worked around it for me now is to do in an oci-env shell: Create /etc/nginx/pulp/timeout.conf containing

proxy_read_timeout 1d;
proxy_send_timeout 1d;

and then s6-svc -r /run/service/nginx.)