Custom pod antiAffinity on helm chart

[christophemorio]

Is your feature request related to a problem? Please describe.
In a multi AZ K8s setup with Helm, replicas are not automatically spread on different AZ.

Describe the solution you'd like
Next to the current value antiAffinity,
Create values gatewayProxies.NAME.customAntiAffinity and gatewayProxies.gatewayProxy.customAntiAffinity, to allow such a flexibility.

Describe alternatives you've considered
Create a second predefined PodAntifinify based on topologyKey: topology.kubernetes.io/zone

Additional context

• ref: https://kubernetes.io/docs/reference/kubernetes-api/labels-annotations-taints/#topologykubernetesiozone
• topologyKey: failure-domain.beta.kubernetes.io/zone is deprecated in v1.17

[kdorosh]

Thanks for reporting @christophemorio . Kustomize or https://docs.solo.io/gloo-edge/latest/installation/gateway/kubernetes/helm_advanced/ can be good options for you today. We'd also love a contribution here to add this to our chart.