Allow for NodePort to be configurable / switched to LoadBalancer

[sylus]

Hi there and thank you for this great project!

I might have noticed one issue leveraging this via AKS (Azure Kubernetes Service) and I think that is because we need to leverage LoadBalancer instead of NodePort which doesn't seem to be supported for this.

Thanks again!

spark-operator/pkg/controller/sparkui.go

Line 58 in 4bf598a

WebUIPort: service.Spec.Ports[0].NodePort,