#1260_add_verifier_to_validation_verification

To resolve issue #1260

Currently verifier is a property of the evidence, however this assumes that there is only one verifier used for each bit of evidence yet it is entirely possible for there to be 2 verifiers involved, one to validate the evidence and one to verify the user is the person the evidence relates too, in fact there might be 2 just for this if they use different providers for liveness and likeness. For example an OP may use a 3rd party provider to check the authenticity of a document and a different provider to do the biometric match of the user to it.

To resolve this verifier should also be a property of validation_method and verification_method