docs: enhance README with comprehensive examples and troubleshooting

[ARUSHIGULBHILE]

This PR significantly improves the Requests README by:

• Adding comprehensive usage examples with practical scenarios
• Including detailed troubleshooting section for common issues
• Enhancing installation instructions with multiple options
• Adding advanced features examples (sessions, file upload, streaming)
• Improving organization with clear sections and better formatting
• Providing error handling examples and best practices

These enhancements make the README more beginner-friendly and practical for real-world use, helping developers get started with Requests more effectively.