Enhanced README.md with a Table of Contents and Comprehensive Updates.

[zeuchie]

Type of change

Documentation improvements.

Description

This pull request significantly improves the OpenNoteScanner project's README.md file to enhance its clarity, organization, and overall user-friendliness. The main changes include:

• Added a comprehensive Table of Contents for easier navigation.
• Restructured the document with clear section headers.
• Expanded the Overview section to include a concise list of key features.
• Improved the Requirements section with clearer explanations.
• Improved the Building from Source section with clearer instructions for Android Studio.
• Retained the project's history and roadmap for context.
• Restructured the Acknowledgements section to properly credit contributors and external code sources.
• Clarified the License information.
• Made numerous grammatical and style improvements throughout the document.