Feature Request: add doorbell event support

[floriske]

Is your feature request related to a problem? Please describe.
At this moment doorbell events like e.g. "button pressed" or "chime rings" aren't available

Describe the solution you'd like
It would be great if the events could be added to the integration so they can be used for automations in HA

Describe alternatives you've considered
I tried creating a very small motion detection area in surveillance station so I could mimick a button press event with the Synology integration but this still also detects motion further away so it doesn't work

P.s. and kind of offtopic but it's great to see that all of your efforts resulted in an update by tp-link so this integration will work again!

[JurajNyiri]

Duplicate of #397

There is currently no known api that would expose this. If it’s available via onvif events or an api is found it could be added.