feat: Add duplicate finder script to find duplicates on any table

[JohanDC-1999]

PR Description:

This pull request introduces a reusable server-side script to find and report on duplicate values for any field on any table. It makes use of GlideAggregate for counts and does basic validations if table and field exists.

Pull Request Checklist

Overview

• I have read and understood the CONTRIBUTING.md guidelines
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[am-shakeel]

@JohanDC-1999 - Description is missing, Please add

[am-shakeel]

🎉 Congratulations on your first approved PR!
Thank you for your persistence and for finally aligning with the contribution guidelines. Your effort is appreciated—keep up the great work and continue contributing to the community!