Implement Wechaty-storage to connect persistent storage with Wechaty data

[windmemory]

It would be great to have a universal storage for Wechaty puppets.

Saving data into persistent storage, such as MongoDB, MySQL, PostgreSQL etc would provide significant convenience for developers. With this Wechaty-storage, developers could create frontend web page easily.

Features:

• define the typings for contact, room, message, tag classes.
• store data into different persistent storage with save schema
• support multiple types of persistent storage
• support convenient switches between different persistent storage

[huan]

It's a great feature!

And I believe this feature is related to Event Sourcing. Here's a great article for it: Event Sourcing made Simple