Add README.txt file

Added readme file.

Hi chaitanyadessai

I installed the module and reviewed your REAMDE.md file, and it seems doesn't follow the README.md template. Missing some sections that are required in the Readme template, for example, the "Requirements" section.
https://www.drupal.org/docs/develop/managing-a-drupalorg-theme-module-or... →

Drupal recommends the following README sections:

Project name and introduction (required)
Table of contents (optional)
Requirements (required)
Recommended modules (optional)
Installation (required, unless a separate INSTALL.md is provided)
Configuration (required)
Troubleshooting & FAQ (optional)
Maintainers (optional)

Thanks