Add a tracking pixel with JavaScript

[MarkEWaite]

Add a tracking pixel with JavaScript

Second attempt at a tracking pixel to see documentation usage.

Testing done

None. Rely on interactive test.

Submitter checklist

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