Add status (binary_)sensor for each device

[postlund]

It's currently very hard to provide decent feedback to the user regarding if the connection works or not. It's also a bit tricky since the same error affects all the entities at the same time, so we would over-report problems. I suggest that we add a new sensor per device, which shows the current state and can include additional error information via attributes. That way we can signal if the whole device is broken or and and possibly also what is broken. I know some other integrations do this as well. Either we keep it simple with a binary_sensor or we use a regular sensor which gives us better feedback via state name.

What do you think @rospogrigio?

[rospogrigio]

Nice idea, I'd go with the regular sensor which can give more info using the state name 👍

[postlund]

Agree, let's take that route!