Use new key attestation library

[inthewaves]

See GrapheneOS/Auditor#320. The attestation code (https://github.com/GrapheneOS/AttestationServer/tree/main/src/main/java/app/attestation/server/attestation) is based on a repo which is now marked as deprecated by Google

New repo upon which to base the code: https://github.com/android/keyattestation

found from: https://developer.android.com/privacy-and-security/security-key-attestation