Add a way for a server to target a specific node pool

[bakayolo]

Is your feature request related to a problem? Please describe. Sixergame has their dev, staging and prod running on the same node pool atm. For security reasons, they would like to segregate their prod services from their dev/staging services. Meaning different node pools running in different subnets.

Describe the solution you'd like Add an "advanced config" for every service so that user can specify "labels" for targetting node pools.