Extract EE specific files/lines for Platform app/controllers/projects

We have the following files containing EE specific code. We should move them to ee/

• app/controllers/projects/deploy_keys_controller.rb
• app/controllers/projects/group_links_controller.rb
• app/controllers/projects/imports_controller.rb
• app/controllers/projects/lfs_api_controller.rb
• app/controllers/projects/protected_branches_controller.rb
• app/controllers/projects/protected_refs_controller.rb
• app/controllers/projects/protected_tags_controller.rb
• app/controllers/projects/refs_controller.rb

A lot of files, but they should all be pretty simple.