zookeeper metrics name contains host id

Issue

• Aggregating metrics from zookeeper nodes is difficult because the metric names are unique for each zookeeper.
• Example of metrics collected by prometheus from zookeeper nodes:
  org_apache_zookeeperservice_replicatedserver_id1_avglatency{.....}
• With different names aggregating metrics from all servers becomes burdensome if number og zookeeper nodes difffer from one cluster to another.