:sparkles: Add support for container restart policy

[linkdd]

Netbox version	Plugin version	Agent version	Docker API Version
3..6.9	1.2.0	N/A	N/A

Actual Behavior

There is no way to specify a restart policy on a container. This means for example, that when the host restarts, the netbox-docker-agent is not restarted automatically, and you can't restart it from Netbox since the agent is not there to start it (oopsie).

Desired Behavior

According to the documentation, we can configure a container to be restarted:

• no: never
• on-failure[:max-retries]: when it crashes (retry at least max-retries)
• always: which is what you would want for the netbox-docker-agent container
• unless-stopped: same as always except if manually stopped

A field should be added to the Container model, as an enumeration, to define the restart policy. The default value should be no. Another field should be added for the max-retries as well.

[fanshan]

@linkdd We will first implement the enumeration. We plan for later the max-retries property.