BLE communication moved to controller class

BLE communication code was implemented in QLowEnergyServiceInfo class.
It is moved now to the QLowEnergyController class.
Needed adjustments are done in order to make this work.

Change-Id: I9206d2324ad59f79f4e035509e23f5c7f7cfb328
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>