Nodetool command is not accessible with read-only account.

In production environment it's important to have comprehensive cluster monitoring. That's where nodetool comes handy. However for security reason tech ops staff gets read-only account and with that account they are unable to pull basics stats like cfstats etc. There is an option to use Rest API but due to security and authentication issues this is not always a valid option. 

Therefore we need to be able to log in to nodetool with RO account and be able to pass aruments which do not change state of Cassandra cluster. 

Another improvement would be to have access to nodetool functions within CQLSH.