Until now, FoodEntryBloc (which is holding the global state for every
day) would cause a change in every widget in the tree. For example, when
an entry for one day gets added, all other entries in opened days would
also be rebuilt.
Now, the GlobalState will be emitted with an additional date, which
signals, which date caused the state change.
With this information, I selectively only build the EntryLists that
needs to be rebuilt.
Additionally, the calendar FAB will push a new route instead of
navigating to a new day by utilizing the pageController.
