Add loadBalancerClass support

What does this MR do and why?

Introduces loadBalancerClass parameter to be used for metallb and kube-vip. This allows the usage of multiple loadbalancers in parallel by targeting specific services based on loadBalancerClass.

The behavior is different between metallb and kube-vip:

• metallb will only serve services having loadBalancerClass: .Values._internal.loadBalancerClass, which here defaults to sylva.org/metallb-class
• kube-vip will serve any service that does not have loadBalancerClass set or if it has loadBalancerClass: kube-vip.io/kube-vip-class which is set here as default

This feature is not really relevant for the management cluster, but it is likely to be required for the workload clusters when the CNF comes with it's own load balancer controller.