Drop Debian packaging

What's currently there makes for a barely functional Debian
package, as it's missing a lot of the expected information such
as copyright and changelog. Plus it contains hardcoded version
information that are several years out of date.

Even if this wasn't the case, there is a strong recommendation
against attempting to maintain the Debian packaging for a
project as part of the upstream repository.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>