docs: Modernize and significantly improve README

Transform README from functional to modern, scannable, and user-friendly.

Major Improvements:

Header Section:
- Added badges: Build Status, License, Version
- Changed from emoji-heavy title to clean, professional header
- Added concise tagline
- Created Quick Start section with complete copy-paste workflow
- Highlighted "That's it!" for confidence

Why systemd-netlogd Section (New):
- Two-column comparison table: "What You Get" vs "What You Don't Need"
- Clear value proposition with benefits and anti-features
- Emoji-enhanced key features (8 features with icons)
- Use cases grid showing real-world applications
- More scannable than previous table format

Installation Section:
- Simplified package installation into clean table
- Made build instructions collapsible (expandable detail)
- Single-flow installation process
- Removed redundant information
- Better visual hierarchy

Configuration Section:
- Common options highlighted (8 most-used options)
- All options in collapsible details section
- Reduced from 7 examples to 5 focused examples
- Added Production TLS example (security-focused)
- Cloud Service examples (Papertrail)
- High-Performance example
- Each example has clear use case
- Link to examples/ directory for more

Advanced Usage Section (New):
- C example in collapsible detail
- Testing and Validation commands grouped
- Practical test commands (nc, logger, journalctl)
- Debug logging setup
- TLS testing command

Security Section:
- Restructured as DO/DON'T with examples
- Security audit command highlighted
- Clear best practices in code format
- Visual distinction with emoji

Troubleshooting Section:
- Four collapsible FAQ-style sections
- No Logs Being Forwarded (4-step diagnosis)
- TLS Connection Failures (4 solutions)
- Connection Refused (3 checks)
- Performance Issues (5 optimizations)
- Quick Fixes section with common commands
- More actionable than previous bullet list

Documentation Section:
- Three-column table layout
- Organized by audience: User/Developer/Examples
- Visual grouping with clear categories
- Easier navigation

Contributing Section:
- Numbered step-by-step process with emoji
- Development commands in code block
- Three resource links clearly listed
- More welcoming tone

Getting Help Section:
- Four-column table with icons
- FAQ, Issues, Discussions, Man Page
- "Before asking for help" checklist
- Guides users to self-service first

License Section:
- Clean, minimal format
- Link to LICENSE file

Acknowledgments Section (New):
- Author credit
- Contributors link
- Project context

Footer Section (New):
- Centered call-to-action for stars
- GitHub stars badge
- Quick navigation links

Visual Improvements:
- Better use of white space
- Collapsible sections reduce overwhelming wall of text
- Tables for better information organization
- Emoji used strategically (not excessively)
- Clear section hierarchy with proper markdown
- More scannable with bold keywords

Content Improvements:
- Removed redundant Examples section (consolidated)
- Removed verbose explanations (kept concise)
- Added Quick Start for immediate success
- Added "Why" section for value proposition
- Better organized troubleshooting
- More actionable commands throughout

Statistics:
- Sections reorganized: 12 → 11 (better flow)
- New sections: 5 (Quick Start, Why, Advanced Usage, Acknowledgments, Footer)
- Collapsible sections: 6 (reduces visual clutter)
- Tables: 7 (improved scannability)
- Removed ~30% verbose content
- Added ~40% high-value content
- Net result: More concise, more useful

Benefits:
- Faster time-to-value with Quick Start
- Better understanding of "why" to use it
- Easier to scan and find information
- Self-service troubleshooting reduces support
- More professional appearance
- Modern README best practices
- Mobile-friendly collapsible sections

Author: ssahani