Add a "gsm signal-profile" command

The previous "gsm signal" command was only letting the user set the RSSI
and BER. This new "signal-profile" commands uses a set of five profiles
corresponding to the signal strength bars displayed on the phone (from 0
to 4, matching one of None, Poor, Moderate, Good, Great).

Signed-off-by: Mathieu Pasquet <mathieu.pasquet@alterway.fr>
Change-Id: If4c0a17af0986e58d11db57140fa9f931bdae8aa
5 files changed