Fixes#440
Adds idiomatic Debian packaging under packaging/debian/.
To build a .deb, symlink the directory to the source root first:
ln -s packaging/debian debian
dpkg-buildpackage -us -uc -b
Files: control, rules (debhelper 13, bootstrap+configure override,
setuid fix in dh_fixperms), cacti-spine.install, cacti-spine.manpages,
changelog, copyright (DEP-5, GPL-2.0-or-later + BSD-4-Clause for
nft_popen), postinst (seeds /etc/spine.conf from .dist on first
install), prerm.
Signed-off-by: Thomas Vincent <thomasvincent@gmail.com>
