Add create-neuron command

[anoop2811]

This is command should create the basic neuron structure and allow it to be created in a chosen folder. If a folder is not given, create it in current folder.
Validations:

1. A name for the neuron is mandatory
2. If a neuron of the same name exists in the folder where it is creating, it should exit with exit code 1 and give an error message to the same
3. Allow a -d flag to create in the directory given. Also validate the directory exists and is writable