net/td-system-info: New port

Printing basic system information and system maintenance

• Submitter becomes Maintainer

PR: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=255576
Reported by: Thomas Dreibholz <dreibh@iem.uni-due.de>
Approved by: garga (mentor)
Differential Revision: https://reviews.freebsd.org/D30098