* config: move AMD root key to global constant
* attestation: add SNP based attestation for aws
* Always enable SNP, regardless of attestation type.
* Make AWSNitroTPM default again
There exists a bug in AWS SNP implementation where sometimes
a host might not be able to produce valid SNP reports.
Since we have to wait for AWS to fix this we are merging SNP
attestation as opt-in feature.
* variant: move into internal/attestation
* attesation: move aws attesation into subfolder nitrotpm
* config: add aws-sev-snp variant
* cli: add tf option to enable AWS SNP
For now the implementations in aws/nitrotpm and aws/snp
are identical. They both contain the aws/nitrotpm impl.
A separate commit will add the actual attestation logic.
