Make it possible to change the MeasurementPolicy used by an AttestationVerifier #15
Description
It might be nice if it was possible to change the MeasurementPolicy used by an AttestationVerifier without re-instantiating AttestationVerifier.
Use case would be:
The measurement policy is retrieved from some resource (file or network). When an attestation fails to validate because of a measurement mismatch, we might want to retrieve the latest version from this resource and re-try the validation.
Whether we would actually want to do this heavily depends on the use-case, and i am not proposing we implement dynamic updating of the measurement policy, only that we make it possible for users of the library to do so if they wish.
Theoretically this is already possible because measurement_policy is a public field on AttestationVerifier. But since AttestationVerifier implements Clone, there is no mutability across clones. So my proposal is to put it in an Arc<RwLock>.