[NEW PORT]: mail/mblaze: Unix utilities to deal with Maildir

The mblaze message system is a set of Unix utilities for processing and
interacting with mail messages which are stored in maildir folders.

WWW: https://github.com/chneukirchen/mblaze

Reviewed by: koobs, mat
Approved by: koobs (mentor)
Differential Revision: https://reviews.freebsd.org/D16759