Only send changed properties to the lamps

[Dirnei]

Xploder mentioned it on discord that state, brightes and so on are always in the payload. It would be better to send only the changed properties to the lamp.

This implies that we should also remove the value from the generic-lamp node and only use the override-nodes.

@Andreas-Huber what do you think of my idea?

[Andreas-Huber]

I think that is a brilliant Idea.
Removing the state from the generic lamp node is definitely a breaking change. But I would make things certainly more clear.