Display uptime/last connected date in dashboard

**Describe the problem you have/What new integration you would like**
As I look at the dashboard, some of my esphome devices are offline. I would like to know how long they have been offline, and/or how long they have been online. Are some offline that should be online?

With 20-30 devices, visually, some are red and some are green, but aside from this binary state, it's hard to know much more about how long they have been offline.

**Please describe your use case for this integration and alternatives you've tried:**
I use some esphome device configurations as "templates" that I duplicate and modify for specific devices. It would be nice to either know that this config has never been online, or was online ages ago. Or that it's "disabled" meaning, that it's not offline at all and shouldn't even try to be online.

**Additional context**
The dashboard is great, but as the number of devices gets large, having the state be only binary online/offline isn't as useful.

Thanks!

Start with the dashboard's existing device-status view and review how it represents online and offline ESPHome devices. Before implementation, define whether done means showing uptime, last-connected time, never-connected state, and/or an intentional disabled state for each device; the issue names no files or tests.

Written by the indexing model from the issue text.