usertools: print process name when telemetry connects

usertools: print process name when telemetry connects

When the dpdk-telemetry client connects to a DPDK instance, we can use the
PID provided in the initial connection message to query from /proc the name
of the process we are connected to, and display that to the user. We use
the "cmdline" procfs entry for the query since that is available on both
Linux and FreeBSD (assuming procfs is mounted on the BSD instance).

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: Kevin Laatz <kevin.laatz@intel.com>