feat: enhance devcontainer and refactor API key page

[kaushalpowar]

This PR introduces several improvements to the project:

1. Enhanced Devcontainer Configuration:

The .devcontainer/devcontainer.json file has been significantly enhanced to provide a more robust and feature-rich development environment. Key improvements include:

• Clearer Naming: The container is now clearly named "Python 3 Development Environment".
• Explicit Settings: VS Code settings are explicitly defined for Python interpreter path, linting, formatting, and editor preferences.
• Essential Extensions: Pre-installed VS Code extensions include Python, Pylance, Black formatter, and IntelliCode for enhanced coding experience.
• Dependency Management: The updateContentCommand is improved for better error handling and clarity in installing system packages and Python requirements.
• Port Forwarding: Streamlit port forwarding is explicitly defined with labels and protocols.
• GitHub Codespaces Integration: openFiles are specified for seamless Codespaces setup.
• Git and GitHub CLI: Git and GitHub CLI are included as features for easier version control.
• Security Enhancements: securityOpt is set to no-new-privileges:true for enhanced security.
• Resource Limits: CPU, memory, and storage limits are defined for better resource management.

2. Refactored API Key Page:

The 0_🔌API_KEY.py file has been completely refactored to improve code structure, readability, and maintainability. Key changes include:

• Modular Design: The code is now organized into functions with clear responsibilities, enhancing readability and testability.
• API Key Validation: Added validation to check if the API key starts with 'sk-' and has sufficient length.
• Error Handling: Improved error handling to provide more informative messages to the user.
• Improved User Experience: Added helpful tooltips and messages to guide the user through the process.
• Type Hinting: Added type hints to improve code clarity and maintainability.
• Docstrings: Added comprehensive docstrings to explain the purpose and functionality of each function.

3. Comprehensive Documentation:

The README.md file has been significantly expanded to provide a comprehensive overview of the project, including installation instructions, usage guide, technical architecture, and troubleshooting tips. A LEARN.md file has also been added to provide more detailed documentation.

These changes significantly improve the overall quality, usability, and maintainability of the project.