reorganize cli command, update doc. Needed for future work with dependency visualizer

[florianbgt]

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Description

We need to change the command name so it make more sense once we implement the dependency visualizer. #45
I also took opportunity to reorganize some functions and files.
Also updated the documentation

• Remove doc link in website (https://github.com/nanoapi-io/nanoland/pull/2)

[florianbgt]

Will rewrite this whole section once we have dependency visualizer. So did not put much effort here. Just added the command. The image was broken