We now have a list of all the features that are implemented, and we can
use that to show a kind of feature list which can be used to -
1. Move away from app rental model
2. Showcase a feature list; see WorkingCopy
Make it a ChageNotifier and try to access it through the Provider
instead of like a global variable. This way, the state is better
managed and it'll be easier to split out Settings into smaller classes.
