Update GitHub issues templates

[glenn-jocher]

New and improved GitHub issues templates.

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Transition from markdown to YAML for GitHub issue templates.

📊 Key Changes

• Deleted old markdown (.md) issue templates for bug reports, feature requests, and general questions.
• Introduced new YAML (.yml) templates to replace the old ones, improving the structure and interactivity of the issue forms.
• Added a new config.yml file to enable direct links to Ultralytics' Slack and Stack Overflow in the issue creation interface.

🎯 Purpose & Impact

• 📝 Enhanced Clarity: The new YAML templates prompt users with more structured and clear forms when they submit issues. This may lead to more detailed and well-organized reports.
• 💬 Better Engagement: The addition of direct help links encourages users to seek community help before creating issues, potentially reducing the number of duplicate or unnecessary issues.
• 👍 Easier Issue Triage: More structured issues make it easier for maintainers to triage and resolve them, improving the project's overall issue management workflow.