rename BluezAdapter to BluezAdapterProperties

We will need a DBus interface for org.bluez.Adapter1 and to avoid
confusion, we rename our current BluezAdapter to BluezAdapterProperties
BluezInterface: use signals to notify that adapter properties changed

This works much more reliable than using the get/set object notifications
BluezInterface: rename BluezAgentManager to BluezAgentManagerBus
BluezInterface: add org.bluez.Adapter1 interface