Track upstream project rename in contrib/blocklistd

Upstream is now https://github.com/zoulasc/blocklist/. Rename the
contrib directory and update Makefiles to match, in advance of the next
vendor branch update.

Sponsored by: The FreeBSD Foundation

pkgbase: Move blacklist utilities to a new package

Unbloat a bit FreeBSD-utilities.
The only package that will depends on this new one is FreeBSD-ssh
which not anyone have in some setup.
And this will allow to have small pkgbase setup with ssh without
having to bring the bloated FreeBSD-utilities package
Name the package blocklist to reflect upstream futur changes.

Sponsored by: Beckhoff Automation GmbH & Co. KG
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D42148

Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Move blacklistd.conf to usr.sbin/blacklistd/

This is prep for pkging base and helps tag and install config files with the
correct packages.

Approved by: bapt (mentor)
Differential Revision: https://reviews.freebsd.org/D16493

Add blacklistd.conf manpage

Install the blacklistd.conf man page, missed in the original commit.

Submitted by: Herbert J. Skuhra ( herbert at mailbox.org )
Reviewed by: rpaulo
Approved by: rpaulo
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D6702

Add basic blacklist build support

Reviewed by: rpaulo
Approved by: rpaulo
Relnotes: YES
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D5913