Add Discord links

[glenn-jocher]

@taliabender YOLOv3 Discord updates to README and README.zh-CN.md

copilot:all

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Enhanced community support and interaction in YOLOv3 documentation.

📊 Key Changes

• Updated the README documentation with links to YOLOv3 Docs, GitHub issue tracking, and Discord community.
• Added Discord social icons and links to the README, making it easier for users to join the Ultralytics Discord community.
• Improved access to Enterprise License information with a direct link.

🎯 Purpose & Impact

• Enhanced Support: Directing users to comprehensive documentation and support channels improves their ability to use and troubleshoot YOLOv3.
• Community Engagement: The integration of Discord invites encourages community-based support, fostering a space for collaboration and discussion among users.
• Ease of Access: Simplified access to licensing clarifies the path for enterprises to engage with Ultralytics services, potentially increasing business inquiries.