Helm chart / values.yaml should support specifying ingressClassName

[mrokitka]

The Helm chart / values.yaml file currently only supports specifying an ingress class via the deprecated "kubernetes.io/ingress.class" annotation. The chart should be updated to support specifying ingress class as a property of the ingress section of the yaml file, which will result in the ingressClassName field being written to the spec of the ingress kube resource.

See:
https://kubernetes.io/docs/concepts/services-networking/ingress/#deprecated-annotation
https://kubernetes.io/blog/2020/04/02/improvements-to-the-ingress-api-in-kubernetes-1.18/

[dpgaspar]

PR from @Jolcik currently on master