RFC: mandatory shape_pt at at most 2m from stop

### Describe the problem

GTFS shapes.txt allows a very funky description of the route over the road. I'll here give two valid examples.
1. Two shape points are defined a kilometer apart, the straight line follows a straight road, a stop is in the center, description within GTFS can be correctly positioned using shape_dist_traveled (in stop_times.txt)
2. Two shape points are defined two kilometers apart, following as the crow flies this is only one kilometer, correctly positioned using shape_dist_traveled (in shapes.txt)

### Use cases

Any system that segments shapes from stop to stop.

### Proposed solution

A new best practise for shapes.txt. When shapes.txt are in use the minimum is a _false node_ as shape_point in the direct neighborhood of the stops.txt entry, at most 2 meters from that position.

### Additional information

_No response_