[enhancement] Move most of FollowPath configuration to path.json files

[Lntnam]

FollowPath configuration variables such as walker, mode, start_mode, no. of laps are heavily depending on the path itself. For example, if the path points are placed along the roads, polylinewalker is not needed.

One may have multiple path files (like I do) with different way of placing map points, different areas, hence the path configuration should follow each path file or at least can be override by the path files' individual configuration.

P.S. Loiter's diameter or max distance should also be set as a global configuration for FollowPath or each path file.