Initial pass at push notifications + some fixes to the session management (#91)

* Fix: test the session during resume to ensure it's valid

* Don't delete sessions for now

* Add notifee and request notif permissions on first login

* Set unread notifications badge on app icon

* Trigger a notifee card on new notifications

* Experimental: use react-native-background-fetch to check for notifications

* Add missing mocks

* Fix to resumeSession()

__tests__/state/models/me.test.ts

@@ -160,7 +160,7 @@ describe('MeModel', () => {
 
   it('should update notifs count with fetchStateUpdate()', async () => {
     meModel.notifications = {
-      refresh: jest.fn(),
+      refresh: jest.fn().mockResolvedValue({}),
     } as unknown as NotificationsViewModel
 
     jest
@@ -173,7 +173,7 @@ describe('MeModel', () => {
         })
       })
 
-    await meModel.fetchStateUpdate()
+    await meModel.fetchNotifications()
     expect(meModel.notificationCount).toBe(1)
     expect(meModel.notifications.refresh).toHaveBeenCalled()
   })