Fix lack of activity log entries, reorganize sensor classes.

[mdrobnak]

Hi there. I have recently been testing both this and ESPresense, and noticed that with the latter, but room names would show up in the activity log as well as the history graph. With Bermuda, that wasn't happening. So that sent me down the rabbit hole of trying to figure out what was going wrong.

The device class that was set effectively blocked it from working, as well as the "state" attribute not being set. Once those two things were done, I noticed your comments mentioned a reorganization of the sensor classes, so I tried my best to logically lay them out for least amount of duplication.

While testing this, I also noticed the Area Switch Reason was more Area Switch Diagnostics - so I added the actual switch reason text as an attribute and gave the sensor that text, and moved the diagnostic text to Area Switch Diagnostic.

As a new user, I also hit into this "why is it going to unknown, that's frustrating" before discovering Area Last Seen, so I set that as a default if people were trying to use this in a lost device in house scenario.

I ran this through the pre-commit checks, so I think from a formatting standpoint this should be OK.

Please let me know if you'd like to see any changes here before accepting.

Thanks for your work so far on this project, it's great!

-Matt