Publish mosaic chains as library.

[deepesh-kn]

This is a follow-up ticket for #54

Currently, the following files are published in index.js

  Directory,
  Logger,
  Node,
  NodeDescription,
  NodeFactory,
  Shell

Instead of exposing files directly, refactor the code and export only the required files

• Remove all the logic from the commander files (bin)

• Move the logic into the new class. (Implementer should name the classes appropriately, )
  AttachChain
CreateChain
ListChain
LogChain
StartChain
StopChain

• Commander files should call these new classes to execute the task

• Expose these class in index.js

• NodeOptions, NodeDescription, NodeFactory should also be exposed in index.js