MINOR: raw_sock: report global traffic statistics

MINOR: raw_sock: report global traffic statistics

Many times we've been missing per-process traffic statistics. While it
didn't make sense in multi-process mode, with threads it does. Thus we
now have a counter of bytes emitted by raw_sock, and a freq counter for
these as well. However, freq_ctr are limited to 32 bits, and given that
loads of 300 Gbps have already been reached over a loopback using
splicing, we need to downscale this a bit. Here we're storing 1/32 of
the byte rate, which gives a theorical limit of 128 GB/s or ~1 Tbps,
which is more than enough. Let's have fun re-reading this sentence in
2029 :-)  The values can be read in "show info" output on the CLI.