Feature request: loadBalancerIP support for the TURN LoadBalancer service

[danielxvu]

As the Kubernetes docs note:

Some cloud providers allow you to specify the loadBalancerIP. In those cases, the load-balancer is created with the user-specified loadBalancerIP. If the loadBalancerIP field is not specified, the loadBalancer is set up with an ephemeral IP address. If you specify a loadBalancerIP but your cloud provider does not support the feature, the loadbalancerIP field that you set is ignored.

It would be useful in my org's case to provision a static external IP address before making cluster changes. Happy to contribute a PR if that's alright with you.

[davidzhao]

@danielxvu sorry that I'm seeing this late. Please do create a PR, we'd be happy to include.