feat: implement CBOR + COSE (backend)

[jurosens]

Feature description

• send data to backend as JSON
• in backend
  • create CBOR
  • calculate hash
  • sign hash
  • create QR code
• return QR code

[a-trzewik]

See example implementation in kotlin (Which can be directly reused as maven dependency) https://github.com/ehn-digital-green-development/hcert-kotlin

The kotlin code is clean and seam to be complete. it can be compiled to jvm library and used directly in java project as maven dependency.

If the functionality should be implemented on backend side than the issue should be move to dgce-issuance-service project

[a-trzewik]

Integrated as maven dependency https://github.com/ehn-digital-green-development/hcert-kotlin see endpoint POST /cert/create available in dev mode profile