Re-purpose the mostly empty "Total Duration" column to "Cumulative Duration."

[indolent]

Description:  When planning a trip, the Total Duration column is empty except for the final trip time at the bottom. I would find it more useful to keep a running cumulative duration adding up all charging and driving accumulated up to each stop.

Use Case: I'm currently planning a two day drive and trying to determine a good place to stop somewhere at or a little after the halfway point. I think it would be nice when planning any multiple day trip to look at the cumulative time to quickly plan an approximate time of driving per day.