Count connections per port

[gfr10598]

tcpinfo should report connections per port, to provide a baseline for understanding any data loss.

We should see tcpinfo files corresponding to the connection counts, ndt files for some ports, ...

[gfr10598]

This should: count connections for each special port, e.g. NDT, prometheus, ssh, http, wss, etc, with port # or string as label. count total connections for all other ports (all) perhaps keep the total bytecounts and duration for each connection?

So, perhaps we should just add a label to the existing tcpinfo stat.