Create queries in bistroContext for data to present in app

Refactor code in BistroContext.

see previous querie code and comments in BistroCard.tsx
the context file need to hande selection of what data to present on screen
Exemple:
What week is week slider presenting?
What day have user selected to show in bistro/map screen?
Witch lunch should be shown in menu when pressed on bistro/map screen function?
What should happen if no data is available? Is the data structure secure so user will never be able to go to MenuScreen when empty on data?

liinnjohansson / todays-lunch