add google backend to crd

[JuHyung-Son]

Closes #410

📑 Description

Add google backend to crd so that operator can support google backend.

✅ Checks

• [x] My pull request adheres to the code style of this project
• [x] My code requires changes to the documentation
• [x] I have updated the documentation as required
• [x] All the tests have passed

ℹ Additional Information