Add display status

[mikenhu]

I just started using this with my HA and it is greatly enhancing my macbook status aside from HA official app. If we can get the status of the display this would be perfect.

[ironcrafter54]

I have stopped working on this repository in favor of just using the home assistant SSH integration. But if you have any experience coding feel free to create a pull request, to add the features you want. I'd be happy to merge it. And if not, since you say you're already using the home assistant companion app that does report the display status. The entity attributes for whether your computer is active or not. Contains information about the display state.