Add a better way to integrate ZHA devices

[xaviml]

Feature Request

Is your feature request related to a problem?

Until now, adding new devices for any integration was as easy as creating a mapping between the fired action of the controller and the action that the event should do. For the case of z2m is easy since all events are string specifying the action that the controller is taking. For deCONZ is more or less the same but with event ID, except the Xiaomi cube where the events are taen from the gesture keyword. However for ZHA is completely different.

In case of ZHA the events fire a JSON with a command (string) and argument (it can be anything). There is no standard established in how the devices should fire events, this is why it depends on the device in specific.

Describe the solution / feature you'd like

What I am aiming in this issue is to be able to easily integrate new ZHA devices by implementing a specific function for each device rather than making it generic as it is until now.

Additional context

This will allow us to integrate the Xiaomi cube for ZHA and the Xiaomi Mijia Smart Switch Round ( #94 ). Until this is not tackled, those devices cannot be yet integrated.

[xaviml]

The integration for this device has been added in ControllerX v3.2.0.