WIP: Fork network

This MR will enable all forked projects to know where the original project is, and will enable us to make MR's from a fork to all other forks of that specific project.

• CHANGELOG entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the style guides
• Branch has no merge conflicts with master (if you do - rebase it please)
• Squashed related commits together

related with #20097 (closed)