feat(providers): Add Riot Games RSO Provider

[ArkShocer]

☕️ Reasoning

Adding Riot Games RSO Provider. Tested it with the current stable next-auth version 4.24.7 on nextjs 14.2.3

🧢 Checklist

• [x] Documentation
• [x] Tests
• [ ] Ready to be merged

🎫 Affected issues

📌 Resources

• Security guidelines
• Contributing guidelines
• Code of conduct
• Contributing to Open Source