Event log parsing requires knowning both the public key and signing
parameters. Symmantically, this information should be from an attested
public key blob, not additional data passed by the client.
Introduce a new method for parsing an AIK's public key blob, returning
a new AIKPublic struct.
* Refactor serialized keys into own structure, in preparation for making Key an interface.
* Refactor key logic into separate structures for each platform/TPMversion invariant.
* Implement review feedback
