Send notifications on new messages

[nickmeinhold]

We are using the firebase_messaging package.

Resources:

• FCM Push Notifications for Flutter
• Configuring APNs with FCM  |  Firebase

[nickmeinhold]

I have an architecture question in the context of receiving notifications - how do we want to make the data in a notification accessible to widgets?

Some initial thoughts I had:

• have a NotificationsService and a corresponding Provider at the top of the tree, where the service receives notifications and has relevant streams that can be listened to
• consider having a global state management solution that receives notifications coming in, has access to the rest of the app state, allowing potentially simpler logic that has been pulled out of the widget tree

What do you guys think? @Jei @tourdownunder