Automatically skip not found hosts when starting container

[FluffyDiscord]

Is your feature request related to a problem? Please describe.
I am migrating to another server. I don't have all services installed yet, but I would like to start nginx-ui to validate and configure what I need before other services. Right now container enters infinite loop when backend isn't reachable. nginx: [emerg] host not found in upstream XXX

Describe the solution you'd like
Monitor nginx startup, if this message shows up, disable that site config and maybe output another warning in logs or show it in the nginx-ui itself.

Describe alternatives you've considered
Manually removing symlinks from the mounted volumes.

Additional context