Generate a traffic plan while avoiding certain waypoints

[Yadunund]

Feature request

Description

The navigation graph for a fleet may have certain "special" waypoints such as those inside lifts or docking waypoints. We do not want robots to be re-routed to such waypoints as part of conflict avoidance as this could inadvertently lead to undesirable actions (robot taking a lift to avoid conflict or beginning a docking manoeuvre). Hence, a way to generate plans without expanding towards such waypoints should be available. However, the planner should still generate plans towards a "special waypoint" if the goal requires the robot to reach such a waypoint.

Implementation considerations

It may be necessary to assign a new attribute to waypoints in rmf_traffic_editor (and hence in exported navigation graphs) to identify such "special waypoints".