calorie data persists with the help of local storage

[gnaaruag]

Refactored app to use local storage for:

• Calorie count
• Deficit goal
• Last update time
• data persistence on closure of web app

this change can act as a layer of security on accidental closure of the app upon which the user might loose an entire days progress.

we could also make it so it will reset itself at 12:00 in the morning but thats not in the scope of this pr