Add audit events schema definitions

What does this MR do and why?

For more info thread discussion here &8944 (comment 1316827698)

Describe in detail what your merge request does and why.

Screenshots or screen recordings

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How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Manual Verification for MR assignees.

This MR was created using a script and we need to verify the details entered in yml files manually. Also, some of the details need to be manually added eg: the description field. Please follow the below steps for each file verification

you can remove this block once MR is ready for review.

1. Check audit name exists in the codebase.
2. Fill description field
3. Check introduced_by_issue, This field was parsed from the branch name so for some of the files it should be correct but for some we need to manually fill it up, refer to MR URL to check the related issue.
4. Check introduced_by_mr is correct.
5. Check milestone is correct.
6. Fill feature_category.
7. Check saved_to_database and streamed are correct.