package/dtv-scan-tables: new package

The dvb-apps package used to carry pre-scanned transponders data. These
transponders data have now been moved out of dvb-apps, and into their
own repository.

So, until we bump the dvb-apps package (to come in a follow-up patch),
dtv-scan-tables is exclusive to dvb-apps.

To be noted: the licensing information for those data is dubious. The
package carries the COPYING and COPYING.LIB files, hinting that the data
is covered by the GPLv2 *and* the LGPLv2.1. This is incoherent, and
dubious:

  - since GPLv2 is a superset of LGPLv2.1, the actual license would be
    just plan GPLv2;

  - the transponders data is just a collection of 'facts': the
    frequencies of each transponder; as such, it is usally not considered
    to be a 'work' as per traditional copyright, and thus should be in
    the public domain [cue the zoneinfo DB not so long ago].

But since this is a difficult question, we'll leave to the user to sort
these things out.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>