Implement backend for badge issuing platform

Need to implement backend for badge issuing platform

Detailed Requirements:
- Need to use open badger specification for API / backend implementation.
https://www.imsglobal.org/sites/default/files/Badges/OBv2p0Final/index.html
- Should be implementing all the classes and API's specified in the specification above.
- Java or Kotlin preferred.
- Microservices / serverless architecture preferred.
- API's should be authenticated. ( email or google auth )
- Should be REST API's
- Design should be scalable horizontally.
- All code should be unit / integration tested.

Reference Badge issuing platforms: https://badge.wiki/wiki/Badge_platforms

Please look into the links and details provided and then ask questions if any clarification needed.

I will need your high level implementation plan, work break down and cost break down before awarding the project.

Ask any specific questions you might have after reading all the above details.