Introduce paper-trail to GitLab

Issue - Backend Gemfile: Introduce paper_trail to gitlab (#479253 - closed)

What does this MR do and why?

We plan to introduce well-known and well-maintained paper_trail gem into GitLab.

As workspace team is planning on using this gem for versioning our agent_config table, see more details with the epic.

This MR is just to introduce the gem with needed approvals, and we will update models with new version tables with follow-up issue.

MR acceptance checklist

• licensing check: MIT License
• appsec review: https://gitlab.com/gitlab-com/gl-security/product-security/appsec/appsec-reviews/-/issues/237

Review the new dependency for quality

• They have an active developer community. At the minimum a maintainer should still be active to merge change requests in case of emergencies.
  • This gem is being widely used and also maintained from its status and history. Check its star and git commit history. https://github.com/paper-trail-gem/paper_trail
• There are no issues open that we know may impact the availability or performance of GitLab.
  • Do not see any major issues from its open issues, https://github.com/paper-trail-gem/paper_trail/issues
• The project is tested using some form of test automation. The test suite must be passing using the Ruby version currently used by GitLab.
  • Check the CI status on the version we use 15.1.0, it runs on ruby 3.2 with Rails 7.1, which is the version GitLab is currently using, https://github.com/paper-trail-gem/paper_trail/tree/v15.1.0?tab=readme-ov-file
• CI builds for all supported platforms must succeed using the new dependency.
  • I think this is mean for GitLab CI builds? There are all green atm, so should be good.

Screenshots or screen recordings

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Before	After

How to set up and validate locally

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