[feat] Add radius to define neighborhood

To define a keypoint, the points neighborhoods are studied. Those neighborhoods were defined only by a number of points. Now, those neighborhoods are also defined by a radius. Points are added while the radius AND the number of points are not reached.

Lines were defined on this neighborhood to compute a curvature. This change allows to remove the rejection of too small lines because the neighborhood must be large enough now.

This fixes some specific use cases when the Lidar is very perpendicular and quite close to a wall, the neighborhoods were small (in terms of space) and always rejected.

The number of points to define a neighborhood is renamed for uniformization