Allow arbitrary annotations for services
We should allow users to configure arbitrary annotations for services. One reason this is helpful, is because on AWS this is a way to pass configuration over to the ELB that will be provisioned: https://kubernetes.io/docs/concepts/cluster-administration/cloud-providers/#load-balancers
Note that the default configuration is to TCP passthrough, so NGINX will still handle the SSL offloading as we would expect. So this is not urgent.