Certificate Declaration verification need to consume real signing keys

[anush-apple]

Problem

The code in GetCertificationDeclarationCertificate in DefaultDeviceAttestationVerifier.cpp is using keys that are test keys for development. We need a generic mechanism to provide a list of keys that can be given to the DA verifier, which can then be used to validate the signature of the CD.

Proposed Solution

Suggest that the CD keys for verification as provided as inputs to the DA verifier similar to how PAA keys are provided in the API and the built-in keys are used as a fallback.