Add healthcheck-related fields to the container`s state

[andrey-yantsen]

What did you implement:

This PR adds support for deserializing of the Healthcheck fields in the docker inspect results (see API for the details).

I'm not sure about HealthStatus::Unknown. Still, I decided to add it to prevent panic when deserializing a response from a hypothetical future docker version, where new health statuses would be added.

How did you verify your change:

I've tried deserializing the docker inspect response, produced by a container with (and without) a health check. Also, I tried the deserialization with/without the chrono feature enabled.