Add streaming metrics

[serban21]

http://cassandra.apache.org/doc/latest/operating/metrics.html#streaming-metrics

[serban21]

Streaming metrics are not visible on new clusters created with ccm. To see them a new node must be added (or an existing one decommissioned), so that some streaming is generated.

After #60 is merged this should also resolve the IPs to hostnames only when explicitly set to do so.