Feature proposal: Email Throttling

[tillchen]

The current system does not include any mechanism to limit the number of emails sent within a certain time period. This can lead to a large number of emails being sent in a short time, especially for large projects with frequent builds or many recipients. This is the gap that the proposed Email Throttling feature aims to address.

We also added the throttle bypassing for critical triggers. This is to ensure that high-impact emails are not lost when there is a throttle. The default for email triggers is to not bypass, while certain important triggers override this value to true.

Note that we have not changed the UI to allow users to configure the email number and time limit. Only admins can change the limits in the code for now. The future plan is to also change the UI to allow the configuration.

Testing done

We have added automated test cases in ExtendedEmailPublisherTest.java.

Submitter checklist

• [x] Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• [x] Ensure that the pull request title represents the desired changelog entry
• [x] Please describe what you did
• [ ] Link to relevant issues in GitHub or Jira
• [ ] Link to relevant pull requests, esp. upstream and downstream changes
• [x] Ensure you have provided tests - that demonstrates feature works or fixes the issue