Intergrate ComfyUI-Manager

ComfyUI-Manager (https://github.com/ltdrdata/ComfyUI-Manager) is an extremely powerful and user friendly add-on. It greatly increases the ease of using custom and community features and packages.

It would be great if this could be integrated as a main component, rather than needing to be found and installed after the fact. Many users won't know it exists, or could have issues getting it set up. It would serve as an excellent add-on system manager.