Drop unmaintained add-on dpfhack

Drop unmaintained add-on dpfhack

This package seems to be unmaintained for at least five years. It's
(former?) upstream traces back to https://section5.ch/index.php/2011/01/13/dpf-hacking/,
but download links to both dpfhack and a patched version of lcd4linux
point to http://localhost/.

http://tech.section5.ch/files/dpfhack-0.1alpha.tgz still serves
something apparently related to dpfhack, but it is unclear whether that
is a previous version than the "0.12devel" we know about, or a
successor. https://tech.section5.ch/files/dpfhack-0.1alpha.tgz, just to
have it noticed, comes with a X.509 certificate not issued for this
FQDN.

dpfhack is solely needed as a dependancy for lcd4linux, which appears to
be unmaintained as well, hence being dropped in a dedicated patch.

Given the status quo, bugs in dpfhack cannot be reported properly,
security issues won't be addressed (by anybody else then ourselves), and
technical questions cannot be clarified aside a reverse engineering
approach.

We should not allow such an add-on to be installed on a firewall system.

Signed-off-by: Peter Müller <peter.mueller@ipfire.org>
Reviewed-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>