Add v2 tpm nonce support

[JoshuaKrstic]

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Add support for V2 TPM nonce

This change will allow the attestation service to generate the V2 TPM nonce.

With this support, the Attestation Service will be able to check attestation evidence with both the V1 Nonce (current challenge) or this new nonce, depending on the prefix of the nonce in the attestation data.

Giving this nonce to the TPM will be in a follow up PR with the rest of the functionality for on demand attestations.