TPM Device Health Checks

[mheese]

This is really one of the core pieces missing where I'm not sure yet what or if it is necessary to do at all.

Kubernetes device plugins have a concept of device health. Currently the implementation reports every device simply as "Healthy".

There are things to consider on how to check the TPM device health:

• for the /dev/tpm0 device we could check if it is actually being used by the host and mark it as "Unhealthy" if it is
• consider running regular "health checks" on the TPM device which could show if the device is truly "Healthy" or not - I'm not sure though what would constitue a good health check here. It also might need elevated privileges for the device plugin container which begs the question if that tradeoff is worth it