package/dvb-apps: add option to install utilities

Previously, dvb-apps was a 'blind' package that would install
only the transponders data files for use by external packages
(namely tvheadend).

Now, we add an option to also install the DVB utilities.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>