Add documentation how to troubleshoot missing events

[christinach]

Introduction

Document how to troubleshoot missing events. This documentation exists in various tickets but since it is sth that we come across often it should exist in the docs as well. Also document AWS existing queues.

Acceptance criteria

• [x] Adds document on how to troubleshoot missing events
• [x] Adds document on the AWS queue with info on how to troubleshoot them.
• [x] It includes workflow: Defines the steps in different environments (production, staging)
• [x] Add information on how to delete information from the dead letter queue in AWS.

This is a follow up ticket on https://github.com/pulibrary/bibdata/issues/2450

[christinach]

Most of the work has been done, documenting what the ticket describes. It's missing information for the different environments: staging and qa. Qa does not have a separate queue so it needs only for staging. Also a workaround on how to delete events from the dead letter queue.