#35161, add a first-time contributor badge

I decided to start by implementing the feature trivially to get better understanding of the workflow and process.

I created a new helper method for this that check if the note author is also the noteable author. If so, a request will be made to see if any merge-request has been merged for this user.

It works for issues and merge-requests. Please review @smcgivern

If the behavior is correct, I will optimize by memoizing the helper's response.

What does this MR do?

Implements #35161 (closed) by adding a "first-time contributor" badge to discussion

Are there points in the code the reviewer needs to double check?

Tests should be reviewed closely.

Why was this MR needed?

This was assigned to me for my technical interview by @smcgivern

Screenshots (if relevant)

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Notes from the same author

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

#35161 (closed)