Binary Sensor, and an easy personalization mechanism for the device_info

I had not needed Binary Sensor yet, but it was very easy to adapt (it's like a Sensor, but simpler).

Now the device_info is generated during the constructor of the Manager. That means that it can be modified by the main application reliably (if I have not messed up). There is an example of how the manufacturer and the model can be set (see the example for inspiration).