Allow user to configure hostPorts in helm chart

[kate-osborn]

The containerPorts for the nginx container do not specify hostPorts. The reason we don't specify hostPort by default is because it goes against Kubernetes best practices. From this doc:

Don't specify a hostPort for a Pod unless it is absolutely necessary. When you bind a Pod to a hostPort, it limits the number of places the Pod can be scheduled, because each <hostIP, hostPort, protocol> combination must be unique. If you don't specify the hostIP and protocol explicitly, Kubernetes will use 0.0.0.0 as the default hostIP and TCP as the default protocol.

If you only need access to the port for debugging purposes, you can use the apiserver proxy or kubectl port-forward.

If you explicitly need to expose a Pod's port on the node, consider using a NodePort Service before resorting to hostPort.

However, we can make hostPorts configurable in the helm chart and allow users to enable them if they need them.

This configuration is supported by our ingress controller: https://github.com/nginxinc/kubernetes-ingress/blob/2e0daa1ad6476a5a4801162bcdf6a932534feba0/charts/nginx-ingress/values.yaml#L132