Add Rails snippet to get group, subgroup, member, requester info

What does this MR do and why?

This MR introduces a GitLab Rails Console snippet that collects and prints error messages associated with groups, subgroups, members and requesters. This is especially helpful for troubleshooting LDAP issues, including those associated with group sync.

Thank you to Harish Ramachandran for providing this snippet.

This was initially developed to assist with solving a ticket 🎫 that is availabel to GitLab team members with access to Zendesk.

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How to set up and validate locally

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MR acceptance checklist

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