use a rubber band selection for moving or deleting multiple waypoints

[ReimarBauer]

Purpose of PR?:

Fixes #1576

mutilselection_example.mp4

with support from claude

[joernu76]

Nice, but this introduces 329 lines-of-code in an already questionable part of the code (this broke a lot in the past) for making it slightly more comfortable to work with (I admit, there are some use cases). In light of keeping things manageable I propose to reject both the MR and the issue.

[ReimarBauer]

We can reopen this issue when we plan to refactor that section of the path interactor. I previously attempted a manual implementation, but we should aim to avoid a situation where a model becomes a necessity for this specific area of the code.