README for PySyft/Notebook Repository

[abhiwalia15]

Feature Description

A new readme section for the pysyft/notebook contents. It will help users to understand the jupyter notebook they are looking for.

Why this feature?

This feature describes and gives a basic structure and overview of the sub-folders in the particular notebook.

Additional Context

The repository is present at: https://github.com/OpenMined/PySyft/tree/dev/notebooks