Summary: - Add MockResponseDetail component to show and edit mocked route - Add `immer` package which will be used for internal state handler Change from PR - Change to functional component Note: - This is a part of this PR: https://github.com/facebook/flipper/pull/488 Reviewed By: mweststrate Differential Revision: D20440149 fbshipit-source-id: d7c35600b9a22cb62c2bdae7e19abe5c767e3670