A car or other transport booking carried its route only in the description, so
a calendar app had no place to navigate to. Without a location of its own, a
transport event now takes the endpoint the traveller has to get to: the
destination of a drive of their own (car, bicycle) and the departure of a ride
they board, the side the per-leg events already use. A car's pickup and
drop-off events are located at their own endpoints. A location the booking
states keeps winning.
Closes#2909
Maurice
067ab89430