Fix that pgdump backup route is broken atm, due to nginx timing out requests before they are established/solidified

[Venryx]

Two routes to solve this:

1. Increase nginx timeout somehow; equal to issue Modify nginx to have a higher query timeout (seems 60s atm) #320. (this is not trivial, as this is a lower level config option that is not exposed directly by nginx-gateway-fabric)
2. Maybe switch to using a graphql subscription after all.