Add row for "All Cars" in Visited dashboard with each car its own colored lines

[lynndixon]

I think it would be great to add another, additional row, in the "Visited" dashboard that combines the maps for all the cars being tracked by Teslamate. Each car could have a different line color to add to the visualizations. This could be in addition to the other rows for multiple cars that shows that cars lifetime visited tracks, that exists now.

I am not great with Grafana, but I am going to poke around and see what I can come up with.