Add more projection modes when moving the gizmos

[YuriSizov]

Currently the PathwayNetwork gizmos are projected to the 3D space using the same logic as the built-in path editor does. The screen space is used as a plane and then the point is put at some distance away from it. This works okay for the top-down view, but not so much for other views, especially when you need to precisely adjust your points vertically.

Thankfully, https://github.com/HungryProton/scatter already does provide a couple more interesting options, including using the plane of the path and relying on colliders (so does https://github.com/Arnklit/Waterways, if I understand correctly).

I've already included the necessary code for those options into the project, but there is no way to toggle between them. Buttons need to be added to the toolbar for that, and the switch needs to be hooked into the logic where appropriate. Functions were not tested yet either, so there may be some bugs. The collider option can also benefit from selecting which physics layers it can interact with.