FR-08: Use Standardized Data Formats

[danisoler-charin]

Description:
All data exchanged between pools shall use standardized data formats as defined in the API specification (e.g., base64-encoded DER for certificates, EXI for messages as per ISO 15118).
Use case:
All scenarios, all endpoints
Status:
✅ This functionality is considered already supported in OPNC v1.0.
Discussion points:

• Confirm that all APIs and examples follow the specified formats.
• Identify where data format rules are defined in the documentation.
• Determine if the validator enforces these formats or if additional validation is needed.
• Clarify whether this should remain a functional requirement or be addressed purely through improved documentation.

My assessment:
This FR seems to be more about documentation and validation clarity than about protocol logic. We may only need to reference or improve documentation to reflect current practice.
Thoughts?