Using rpk container should show errors from container startup

[voutilad]

Who is this for and what problem do they have today?

For users of rpk container commands, specifically rpk container start, they're purposely choosing to not interface directly with Docker. If there's a problem starting Redpanda, users will often just see an error like:

Error: unable to dial: dial tcp 127.0.0.1:41719: connect: connection refused

What are the success criteria?

User should receive a more descriptive message about why Redpanda is not running instead of just that rpk cannot connect to the admin/kafka api ports.

Why is solving this problem impactful?

It surfaces the root cause of the failure and not a consequence (i.e. lack of network connection to the cluster). The actual error can be shared with others (support, community Slack, etc.) and cut down on time wasted troubleshooting.

Additional notes

JIRA Link: CORE-1417