Combine Deploy Keys and Push Rules and Mirror Repository and Protect Branches settings pages

Resources

PM @victorwu | UX @tauriedavis

Background

Part of #23007 (closed).

Scope for this issue

• For a given project, combine the existing pages into a single page.
  • For EE:
    • Deploy Keys
    • Push Rules
    • Mirror Repository
    • Protect Branches
• For CE:
  • Deploy Keys
  • Push Rules
• Call this single page the Repository page.
• Update the gear/cog navigation. Combine the above navigation menu items into one menu item called Repository.