Stop using PagerDuty

We currently only rely on pager duty for emails. We could achieve this by setting up SNS topics and subscribing out team's email to notifications when alarms are triggered.

First we need to create a list of all the alarms that need to be moved by going through PagerDuty and add that as a task list to this ticket. Some may be configured in the frontend and other repos. All alarms should be in the frontend AWS account.