dns/dnsjit: New port: Engine for capturing, parsing and replaying DNS

dnsjit is a combination of parts taken from dsc, dnscap, drool, and
put together around Lua to create a script-based engine for easy
capturing, parsing and statistics gathering of DNS messages while
also providing facilities for replaying DNS traffic.

WWW: https://github.com/DNS-OARC/dnsjit

Originally submitted by pi, updated by Leo Vandewoestijne and I made
some minor fixes on top of Leo's patch

PR: 235461
Approved by: arrowd (mentor)
Differential Revision: https://reviews.freebsd.org/D32268