removed `NavigateTowards2dNodes` attribute, instead push parent values downwards by searching appropriate component (fixes #20)

[Abb4]

• fixes #20

• apparently the reference to NavigateTowards2dNodes by NavMesh2DSeeker as an attribute is what caused the error

  • I used the reference in NavMesh2DSeeker to push values set in the editor downstream to the component
  • I implemented the reference that way so that we could configure the scene from the editor and did not have to GetNode to find the component
  • Now I just use GetNode (specifically TryFindNodeInChildrenRecursively helper function)

(Yes it was neither the cashe nor the naming 🙈)