WIP: Moving settings cog to navigation tab

Originally !6999 (closed) by @lukehowel

What does this MR do?

Moves settings from cog dropdown to navigation tab per layout in #23007 (closed)

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

⚠ This MR depends on !7600 (merged) to be merged, so the target branch is currently 23305-leave-project-and-leave-group-should-be-buttons, it will be changed to master when !7600 (merged) is merged.

Why was this MR needed?

Design decision was made to move settings to navigation tab

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• 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 #23007 (closed)