Publish metrics for connected clients with user stats

There are metrics being published for connected clients. But if we want to find why connection count went up or down, it would be better to expose connections per user stats. (i.e. Some auth info for the connection)

Introduce new `clnt` command which is similar to `cons` except this also displays the user-agent to identify the type of client used to connect. List full connection/session details for all clients connected to this server. Includes information on numbers of packets received/sent, session id, operation latencies, last operation performed, user-agent, etc...