Show example output of command

[pederhan]

On the in-depth documentation page of each command, there should be a (collapsed?) section showing the typical output of the command.

We need to figure out if this should be text or an image. If we do text, we have no way to colorize the output unless we use HTML. In order to do HTML, we need to record Rich console sessions and export them as HTML. That might be too much work for now, as this process would definitely require automation, and there is currently no test Harbor instance that can be relied on to provide this service.

Either way, the examples should probably go in docs/commands/examples/<full_name_of_command>.<ext>, i.e.: docs/commands/examples/artifact_list.png

The template (docs/templates/category.md.j2) would then have to be modified to load this file based on the name of the command currently being rendered.