Saldi i vagtplanen

In case of overlapping ClosedSicknessState, we add the days to hours_worked
In case of overlapping WishType::UNAVAILABLE, we do not add to hours_worked but rather actual_vacation_hours
In case of WishType::NOT_WORKING_BUT_NOT_SUBTRACTED, we do not add to hours_worked nor actual_vacation_hours (so users can place that as a note on top of a shift!)