Deprecate and remove publickey(5) stuff

From: Emmanuel Vadot <manu_at_bidouilliste.com>
Date: Wed, 15 Dec 2021 16:55:08 UTC
 Hello, it's me again,

 I've posted some review some time ago but didn't follow up with some
mail so users might see it.
 I'd like to remove publickey(5) related programs, those are the only
DES users iirc and likely unused.

 https://reviews.freebsd.org/D30682
 https://reviews.freebsd.org/D30683

 I'll commit this in two weeks unless there is some valid argument to
keep this.

 Cheers,

-- 
Emmanuel Vadot <manu@bidouilliste.com> <manu@freebsd.org>