Find node for geo position

[paulheinr]

src/parallel_simulation/routing/router.rs:95

Computing distance to every node is slow (https://github.com/RoutingKit/RoutingKit/blob/master/doc/CoordinatesToNodeID.md). Look for other options.

[paulheinr]

Not needed any more, because we route between links. To the rust road router we pass the start/end node of the link, thus we don't need this search any more. Done in #50