Add MobX store for Requests (and likely other things) #35
Description
This would set us up with a system where we can cache info, so there are less loading screens overall in the app.
Wouldn't be too hard, you need to store the list of requests, and just have ways of invalidating the data and making it refresh automatically if it is out of date (could be after a certain amount of time, or if the user refreshes the dashboard by pulling down).
Possible Issues:
- Distinguishing between the tabs on the dashboard - how do we store 'Main' differently from 'Self' and 'Joined'?
- Making sure logic to refresh is handled well, otherwise could fail easily and cause random errors
- Making a loading overlay work with this (likely would have to integrate some sort of global overlay as well)