Use dynamic meal schedule in helpers

[EricPedley]

Right now, get_current_meal in helpers.py uses hard-coded times to separate each meal, but it should read from the schedule data in location_management.py to figure out the meal schedule. Specifically, on weekends dinner starts at 3:30 PM but on weekdays dinner starts at 4:30 PM. We could hard-code that but I think it's better to dynamically read the schedule.