docs: improve LEARN.md and README.md

[kaushalpowar]

This PR significantly enhances the LEARN.md and README.md files to provide a more comprehensive and user-friendly experience. The changes include:

Improvements to README.md:

• Added Badges: Badges have been added to clearly showcase the project's technology stack (Python, Streamlit, OpenAI) and license.
• Improved Structure: The README now follows a clearer, more logical structure with dedicated sections for features, installation, requirements, usage, architecture, security, troubleshooting, contributing, license, and contact information. This makes it easier for users to find the information they need.
• Detailed Explanations: Each section provides more detailed explanations and examples, making the README more informative and accessible.
• Quick Start Guide: A concise quick start guide has been added to help users get up and running quickly.
• Technology Stack: A dedicated section outlines the project's technology stack, providing clarity on the tools and libraries used.
• Key Benefits: A section highlighting the key benefits of using the application has been added.
• Acknowledgments: Added a section to acknowledge the contributions of OpenAI, Streamlit, and LlamaIndex.
• Removed Redundancy: Unnecessary or repetitive content has been removed to improve clarity and conciseness.

Improvements to LEARN.md:

• Improved Structure and Content: The document now has a more organized structure with clear headings and subheadings. The content has been expanded to provide more detailed explanations and examples.
• Detailed Usage Instructions: The usage instructions have been made more comprehensive and easier to follow.
• Troubleshooting Section: A new troubleshooting section has been added to address common issues and provide solutions.
• Contributing Section: A contributing section has been added to guide potential contributors on how to contribute to the project.
• License and Contact Information: License and contact information have been added for clarity.
• Architecture and Security Sections: New sections dedicated to the project's architecture and security considerations have been added.

These changes aim to improve the overall documentation quality, making it easier for users to understand and use the application, and for contributors to engage with the project.