net/tcpstats-{kmod,reader}: Add new ports

tcpstats-kmod is a FreeBSD kernel module that exports per-connection
TCP socket statistics via a /dev/tcpstats character device.
Provides 320-byte fixed-size records containing addresses, ports,
TCP state, congestion control parameters, RTT measurements,
retransmit counts, and ECN state.
Includes a tcpstats(4) man page.

tcpstats-reader is a companion CLI tool that reads from /dev/tcpstats
and outputs JSON Lines to stdout.
Includes a tcpstats-reader(1) man page.

WWW: https://github.com/randomizedcoder/bsd-xtcp

Signed-off-by: randomizedcoder <dave.seddon.ca@gmail.com>
Approved by: fuz (ports)
Reviewed by: fuz, pouria
Pull-Request: https://github.com/freebsd/freebsd-ports/pull/497