configure turn cost calculation

[karussell]

Attempt to fix #1590.

Use cases:

• avoid left turns for motor vehicles
• avoid zig zag routes e.g. for bike like described in Prefer cycleway=lane for bike #1500.
• avoid dense areas via avoiding too many junctions to get similar results like when using urban_density and avoiding CITY.
• exclude too sharp turns for e.g. trucks.

Configuration to avoid zig zag routes for bike:

  graph.encoded_values: orientation
  profiles:
    - name: bike
      turn_costs:
        left: 6
        right: 6
        vehicle_types: [bicycle]
      custom_model_files: [bike.json]

The implementation fills an orientation encoded value where the forward value stores the orientation of the end segment of the edge and the backward value stores the orientation of the start segment of the edge. With that all turn angles can be calculated. Of course sometimes a "left turn" cannot be detected from the angle alone and topology must be considered but for now this orientation approach works good enough (and the topology approach did not work that well alone when I tried it before).

A more sophisticated implementation could also use different turn costs depending on the country or road_class but this and a request-based customization of the turn costs (moving it into the custom_model) should not be part of this PR.