Refactor point interpolation into motion model

[Kyle Williams]

If we refactor the interpolation into the motion model, then we can store the point positions inside the motion model. We would then only need the member function interface

• __init__
• update_points()
• interpolate_points(t: float)

This will require storing the points and the old points internally, which would be updated and returned whenever update_points is called. interpolate_points would simply interpolate between the old and the new points and return them.

This will completely encapsulate the motion model data from the rest of the program