GTFS: Use postgis to get existing nodes when aggregation radius is 0

[tahini]

fixes #908

Since KDBush sometimes does not return a node which is at the exact location as another one, the main code path sometimes created new nodes at the exact same location when the aggregation radius was set to 0. postgis, on the other hand, does not do that, so we get the existing node from the database in that case.

Also

• Move getNodesInBirdDistance to NodeCollecitonUtils
• Add a db and utils functions to get nodes withing distance of a point (one already existed for existing nodes)
• Run yarn format on the code

[tahini]

@greenscientist cette PR va faire des conflits avec ta branche actuelle

[greenscientist]

@greenscientist cette PR va faire des conflits avec ta branche actuelle

Ouais, expected! Mais comme je sais pas ça va prendre combien de temps régler la mienne, c'est bon.

[tahini]

@greenscientist Le dernier commit ajoute des validations de la présence des transferable nodes dans la cache.