As the common.h is only meant to be used by the network
shell files, rename it to be more descriptive in order to
avoid possible conflicts with any other common.h file.
Signed-off-by: Jukka Rissanen <jukka.rissanen@nordicsemi.no>
The interface number is generated automatically if one
presses <tab> when expecting the interface.
Signed-off-by: Jukka Rissanen <jukka.rissanen@nordicsemi.no>