Clean up Maven Central files

🧹 Cleanup:
- Removed MAVEN_CENTRAL_SETUP.md
- Removed publish-to-maven-central.sh
- Focused on JitPack auto-detection only

✅ Ready for JitPack v1.2.5:
- Clean repository
- No conflicting configurations
- JitPack auto-detection should work

Author: mabualzait