Use CommIOSNotifications in AppDelegate and in JavaScript to request permissions

Summary: This differential uses CommIOSnotifications in AppDelegate notification - related callbacks and in JavaScript to request and validate notification permissions.

Test Plan: Build the app, after uninstalling it. Application should: ask for permission, receive foreground notifications, background notifications and correctly rescind when read on another machine.

Reviewers: tomek, atul, ashoat

Reviewed By: tomek, ashoat

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D6071