Python: Add support for sweep arranger for the ROUTING_SWEEP strategy.

I am trying to set First Solution as SWEEP to be able to get the optimizer running with cluster of nearby drop point instead of having expanding tree.

```py
# Setting first solution heuristic.
search_parameters = pywrapcp.DefaultRoutingSearchParameters()
search_parameters.first_solution_strategy = (
routing_enums_pb2.FirstSolutionStrategy.SWEEP)

# # Setting first solution heuristic.
# routing_enums_pb2.FirstSolutionStrategy.PATH_CHEAPEST_ARC)
search_parameters.local_search_metaheuristic = (
routing_enums_pb2.LocalSearchMetaheuristic.GUIDED_LOCAL_SEARCH)
```

However, I encounter this error
Invalid RoutingSearchParameters for this model: Undefined sweep arranger for ROUTING_SWEEP strategy.

Is there another way to have cluster of point server by the same route ?