Resolve "Simplified Repository Settings page"

EE Port: gitlab-ee!2029

What does this MR do?

Changes the settings page in Project -> Settings -> Repository to include expandable sections.

Are there points in the code the reviewer needs to double check?

Searching with ctrl+F (or CMD+F on macOS) should auto-expand settings sections when a match is found.

Screenshots

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #30378 (closed)