Feature/email template clean

[Daniel-VM]

PR Checklist

• A clear and concise description of the changes is included in this pull request, along with the reasons for the changes.
• All code has been linted and meets the repository's style requirements.
• Any warnings or errors observed during testing have been addressed.
• The CHANGELOG.md file includes a summary of the changes made in this PR.
• The README.md file has been updated if applicable, including new references, contributors, or tools added.

PR description:

• Send access request notifications as multipart plain-text and HTML emails.
• Replace raw access labels with a structured use-case and role summary.
• Keep internal permission group details visible only in use-case admin notifications.
• Show the use-case section link to users only after their request is approved.