Create documentation for how to use the packages in the packages folder

[ResuBaka]

What is the motivation for adding/enhancing this feature?

Here every body needs to know what he needs to do when he adds to packages in the folder and how it overall functions so it is easy to understand why it is there it the first place.

What are the acceptance criteria

• Why is the package folder there
• How to use the package folder
• What use has the package folder
• When to edit something in there

Can you complete this feature request by yourself?

• YES
• NO

Additional information

The package folder is there for two things first to don't have imports like this ../../../../../lib/db which we had after fixing that the dist/src/index.js could be called and would not throw an error. The second reason is that in the long run you only install the packages you want and not git clone the hole repository to use the storefront-api.