Add AIGW service class for summarize_review

Alejandro Rodríguezrequested to merge
summarize-review-prompt-migration into master

What does this MR do and why?

Part of #495131 (closed)

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

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Before After

How to set up and validate locally

  • Enable the FF: Feature.enable(:ai_gateway_agents)
  • Start a MR review and use the GitLab Duo button to generate a summary

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