generating directory index in Markdown

[mstgnz]

Description:

This pull request aims to refactor the README file of the educational repository written in the Go programming language. Currently, the README file is empty and contains nested directories extensively. To address this, I have added a program written in Go.

Changes Made:

• Added a new Go file named index.go.
• The program traverses the nested directories in the project to create an INDEX.md file.
• The generated INDEX.md presents the directory structure of the project in a more understandable manner.

same this #72