feature(monitoring node): enable node_exporter on monitoring node
feature(monitoring node): enable node_exporter on monitoring node

since we had issue with monitoring, we want to collect cpu/mem and such from
the node running the monitoring

Ref: https://trello.com/c/qyttIBBi

scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests