Revert "Allow accessing deviceName from qml"

This reverts commit e47fb17006.

It broke the name in various QML places because display was not available as a role any more. The ones inside KDE Connect were easily fixed, but Purpose is hard to fix
in a fully compatible way

interfaces/devicesmodel.cpp

@@ -70,7 +70,6 @@ DevicesModel::DevicesModel(QObject* parent)
 QHash< int, QByteArray > DevicesModel::roleNames() const
 {
     QHash<int, QByteArray> names = QAbstractItemModel::roleNames();
-    names.insert(NameModelRole, "deviceName");
     names.insert(IdModelRole, "deviceId");
     names.insert(IconNameRole, "iconName");
     names.insert(DeviceRole, "device");