Adding support for IDevID and IAK

# Enhancement Description
- One-line enhancement description (can be used as a release note): Leverage the IDevID and IAK keys/certificates to register each device at the registrar service and enable attestation based on the IAK instead of using an ephemeral AK (Attestation key).
- Keylime Enhancement Proposal: https://github.com/keylime/enhancements/pull/82
- Primary contact (assignee): @gustavobbrand
- Enhancement target (which target equals to which milestone):
- Alpha release target (TBD)
- Beta release target (TBD)
- Stable release target (TBD)

_Please to keep this description up to date._

Start by reading the linked Keylime Enhancement Proposal #82 and the issue's description of IDevID and IAK registration at the registrar service. Identify the relevant implementation entry points and tests from there; the work is complete when devices can register with those credentials and attestation uses the IAK rather than an ephemeral AK.

Written by the indexing model from the issue text.