Epic: nerdctl namespace issues

[apostasie]

Description

• both namespace update and namespace inspect with non-existing namespaces (with possibly invalid names) do not error, and return results (test for: " ", "_", "∞", "")
• if multiple identifiers are passed to inspect, it will return a len(array) > 1 of bogus results
• namespace update should enforce the presence of a --label, as updating without any does not do anything
• namespace list should support a format argument
• namespace inspect, namespace remove and namespace update should have completion on namespaces names
• namespace inspect format support is questionnable: by default, inspect outputs valid json, but with --format json, it will output a stream of json entries - table and wide are not supported
• namespace inspect should at least have the same information available on namespace list (inc. number of volumes, containers, labels, etc)

Steps to reproduce the issue

No response

Describe the results you received and expected

na

What version of nerdctl are you using?

main

Are you using a variant of nerdctl? (e.g., Rancher Desktop)

None

Host information

No response

[apostasie]

Should be a good set of "good first issues", and it should be relatively straightforward to fix these.