Allow custom annotations for servicePublishingStrategy loadbalancer services on hostedclusters

Extend the hosted cluster CRD with the possibility to add customs annotations for services type loadbalancer created by the service publishing strategy:

...  
  services:
  - service: APIServer
    servicePublishingStrategy:
      type: LoadBalancer
      loadBalancer:
        hostname: api.species-8472.clusters.blahonga.me
        annotations:
          metallb.universe.tf/loadBalancerIPs: 10.1.1.123 

This would allow for selecting specific metallb pools or specific ip adresses when a hosted cluster is created thus allowing control of exposed services adressing.

This is primarily useful when using metallb but would be useful also for other loadbalancer providers such as the AWS Loadbalancer controller: https://kubernetes-sigs.github.io/aws-load-balancer-controller/v2.11/guide/service/annotations/