Remove the need of using platform dependent code for address parameters in Bluetooth classes

In QBluetoothDeviceInfo, there exists the method deviceUuid() as a workaround for OS X and iOS, because those two platforms do not provide Bluetooth addresses as all other platforms do.

Unfortunately, this workaround is not used consequently in other classes, see e.g. QBluetoothLocalDevice (QTBUG-53331) or QLowEnergyController (QTBUG-52690). Even if these workarounds would be implemented in all relevant classes, this would force me to write platform specific code all the time. This is definitivly not what I want when using a framework like Qt, which targets to be platfom-INdependent.

I therefore suggest to allow the use of QString as address parameter in all relevant Bluetooth methods. Internally, this parameter could be converted to either QBluetoothAddress or QBluetoothUuid, whatever is needed on the specific plattform. I would really appreciate if you would increase platform independency in this or in a similiar way.

Edit: See also QTBUG-59086.