feat: updated external-dns chart to use official chart

[Ani1357]

📌 Summary

🔍 Reviewer Notes

🧹 Checklist

• Code is readable, maintainable, and robust.
• Unit tests added/updated

[merll]

I tested this with a Helm install, and encountered two issues:

• ORCS cannot be used yet, as we have only added the Bitnami image
• The pod fails to start up with the following messages, when I update the Application

time="2025-10-03T12:11:49Z" level=error msg="Edgegrid Init Failed"                                                                                                                
time="2025-10-03T12:11:49Z" level=fatal msg="Unable to create instance using environment or .edgerc file"

Could you also update the Chart index with the source?

[merll]

Please follow name conventions for creating resources