Bug#968011: Dedicated non-public executable to get latest policy version from Lintian data

[Felix Lechner <felix.lechner@lease-up.com>]

Control: clone -1 -2
Control: retitle -2 Stop shipping private/latest-policy-version
Control: unblock -1 by 968000 968154

> the interface is scheduled to change again in the near future.

Lintian will soon stop shipping its modules in the Perl system path.
For the benefit of libconfig-model-dpkg-perl (and only for the benefit
of that package), Lintian will instead provide a dedicated program to
obtain the latest policy version from Lintian data.

The location of the non-public executable is

    /usr/share/lintian/private/latest-policy-version

Kind regards,
Felix Lechner