Restructuring of planner

[maxspahn]

As suggested in the talk by Nathan, https://www.youtube.com/watch?v=VsM-kdk74d8&list=PL_oEZ6dld4ignAdbFvcP_LAJgNbdrNBKC&index=10, it seems better to clearly split between geomtry and forcing policy.

This should also be reflected in the code structure. Potentially, the pure geometry should be serialized so that the forcing can be changed at runtime easily.