Add user roles framework and Slack polling strategy

[amanrj03]

## Summary
This PR adds a comprehensive user roles framework and Slack polling strategy to better understand and serve the AboutCode community's diverse needs.

## Changes Made
- **User Roles Framework**: Defines 10 distinct user types with attributes like technical level, compliance/security interests, and experience levels
- **Slack Polling Strategy**: Systematic 4-week approach to validate user roles through community engagement
- **Ready-to-Use Messages**: Copy-paste Slack messages and polls for immediate implementation

## Files Added
- `user-roles-framework.md` - Comprehensive user role definitions and usage guidelines
- `slack-polling-strategy.md` - Detailed polling methodology and analysis framework  
- `slack-messages-ready-to-use.md` - Ready-to-copy Slack messages for community research

## Benefits
- Better understanding of community composition and needs
- Data-driven approach to documentation and feature prioritization
- Improved user experience through targeted content creation
- Systematic method for ongoing community feedback collection

## Testing
- All documents are well-structured and ready for immediate use
- Slack messages are tested for clarity and engagement
- Framework covers the full spectrum of AboutCode users

## Related Issues
Addresses the need for better understanding of user roles and community needs as discussed in community channels.

Additional Options:

• ☑️ Allow edits from maintainers (recommended)
• Add labels if available (like documentation, community)
• Request reviewers if you know specific maintainers