Design an instant messaging app similar to WeChat. It should have a user self-registration function without requiring a mobile phone number. There should be a department selection option, and the departments are set up in advance in the background. The app should possess features such as a contacts list, group chats, friends, a Moments-like function where users can post and share, the ability to send image and video materials, a live streaming function, an album and journal similar to QQ Space, and a message board function.