Enhance README with detailed sections and add a screenshot

[brandochn]

This pull request significantly enhances the README.md to provide a more comprehensive and user-friendly overview of the Light Query Profiler project. The documentation now covers both the desktop application and the new Visual Studio Code extension, details key features, and improves onboarding instructions for users and contributors.

Documentation improvements:

• Expanded the project introduction to clarify that Light Query Profiler is available both as a desktop app and a VS Code extension, with updated badges and links to the VS Code Marketplace.
• Added detailed sections for Features, Requirements, Authentication Modes, Supported Platforms, and Known Issues to better inform users about capabilities and limitations.
• Included step-by-step instructions for installing and using the VS Code extension.

Contribution and project status:

• Added a Contributing section with clear steps for submitting changes, and updated the Status section for clarity.

Formatting and visuals:

• Improved formatting, added a screenshot, and reorganized the Table of Contents for easier navigation.