Passing objects as string between activities/fragments should be removed

[MarkusAJacobsen]

There are some places where the objects are passed between activities and fragments. This is fine as long as the model can't change in between, this is the case after modify. Overview* should call network client to fetch this data instead

[MarkusAJacobsen]

Fixed with the usage of the Firestore Client implementation. All mutable situations will rather fetch data online than static transfer