Refactor the components design

[wj-Mcat]

Description

All of itchat method is encapsulated into split module, eg: contact, login, message, hotreload, which is attached to the Core object. Because all of submodule in components module is in the same class: Core, so we can pack all of methods into one Object: AsyncItchat which is the async-based itchat.

Design

In this case, all of methods in components is in same class and there are so many common codes can be refactored. I believe if this change has been done, it will make code smaller and more elegant.