Changes from 5.8:

- Algorithm:
  - Multi-Level Dijkstra:
    - Plugins supported: `table`
    - Adds alternative routes support see #4047 and #3905: provides reasonably looking alternative routes (many, if possible) with reasonable query times.
- API:
  - Exposes `alternatives=Number` parameter overload in addition to the boolean flag.
  - Support for exits numbers and names. New member `exits` in `RouteStep`, based on `junction:ref` on ways
  - `RouteStep` now has new parameter `classes` that can be set in the profile on each way.
- Profiles:
  - `result.exits` allows you to set a way's exit numbers and names, see `junction:ref`
  - `ExtractionWay` now as new property `forward_classes` and `backward_classes` that can set in the `way_function`.
     The maximum number of classes is 8.
- Node.js Bindings:
  - Exposes `alternatives=Number` parameter overload in addition to the boolean flag
- Tools:
  - Exposes engine limit on number of alternatives to generate `--max-alternatives` in `osrm-routed` (3 by default)