Refactor Position

[benn02]

Currently, objects that can be on the map have a deprecated position property. Since objects don't have to be on the map, this property can then be undefined.
This is insufficient because some of these objects can have different positions that are off the map. Therefor, we have introduced the MetaPosition that encapsulates all sorts of positions on and off the map.
The MetaPosition is present where it is needed, but doesn't replace position in all classes.
This issue is about replacing position properties in all classes and get rid of all of its usage. Also get rid of the Position Class.
This is also about refactoring of associated Logic when the position is undefined and make things more explicit.
When all usage of position is gone, we could rename the MetaPosition to Position.

Requirement: M6b