Document the need for this package

With expo 38 the expo system brought new Notifications that are delivered directly over websocket, pretty much like this package does. That might be understood as: we will loose all the merits of this package, but that is not the case:

This package will allow us to send a lot of notifications directly through our server, rather than expo. Which creates a lower dependency and the notifications are not handled by a third party. We also might have the opportunity to switch it out for a notification system that is a little bit more "closer to the metal" for react-native without expo, in case we eject at some point. Furthermore: by having control our own solution we are in the position to experiment with truly decentralized notification systems.