[commhistory-daemon] Simplified SmartMessaging

New and improved QOfonoSmartMessaging can follow the changes in the modem
interface list and update its 'valid' property accordingly.
[commhistory-daemon] Add prefix to SmartMessaging debug output
[commhistory-daemon] Require libqofono-qt5 >= 0.66
Merge pull request #61 from monich/smartermess

Simplified SmartMessaging