Add home GPS coordinates to device tracker

**Is your feature request related to a problem? Please describe.**
A Bermuda's device tracker only provides information whether a user is home/not home, but no GPS coordinates. When assigned to a user, this information is then passed to User's entity. The map card then cannot show my user on the map (in home zone) because of the missing coordinates.

**Describe the solution you'd like**
When Bermuda's device tracker entity is in "home" state, it will have defined GPS coordinates attributes that will be identical to GPS coordinates of Home zone.

**Describe alternatives you've considered**
Since map view is important to me (even when users are home), the only solution I found to get my users on the map was _not_ using Bermuda's device trackers.

**Additional context**
Just to be clear, I'm not requesting GPS coordinates when the tracked device is outside of home - that's of course impossible.