Follow-ups on consolidate_intersections

[martinfleis]

The consolidate_intersections now works on OSMnx graphs but to make it work on a generic graph generated via ´gdf_to_nx`, it requires #546 and a specific setup:

graph = mm.gdf_to_nx(auckland, length="length", integer_labels=True)
nx.set_edge_attributes(graph, {edge: {"from": edge[0], "to": edge[1]} for edge in graph.edges})

The last bit is fairly redundant as it encodes the information about the edge nodes as attributes. No clue why osmnx does that in the first place but would rather avoid that in gdf_to_nx so we should probably do that on-the-fly in the function itself.