Push notification & session management cleanup (#92)

* Add some temporary logging to help suss out the session drop issue

* Fix to session resumption: copy session tokens during a resumeSession attempt

* Factor out notifee display into a lib and add to storybook

* Tune the bg notifications fetch to only get what is needed

* Fix: run account update inside a mobx action

* Remove debugging logs for sessions

* Fixes to bg notifications fetch

src/state/models/root-store.ts

@@ -136,8 +136,7 @@ export class RootStoreModel {
   async onBgFetch(taskId: string) {
     this.log.debug(`Background fetch fired for task ${taskId}`)
     if (this.session.hasSession) {
-      // grab notifications
-      await this.me.fetchNotifications()
+      await this.me.bgFetchNotifications()
     }
     BackgroundFetch.finish(taskId)
   }