get nodegroups command no longer display all nodegroups

What happened?
You can no longer get all nodegroups via a single command. You can only get individual nodegroup settings.

What you expected to happen?
Expect to display all nodegroups without entering a nodegroup name, which was capable in v0.3.1. At least another flag/option to display all groups.

How to reproduce it?
eksctl get nodegroup --cluster amg-non-prod-use1
[✖] nodeGroups[0].name must be set

Versions

eksctl version
[ℹ]  version.Info{BuiltAt:"", GitCommit:"", GitTag:"0.4.0"}

[2opremio]

This seems to have happened in dbedfd1 (part of #859 ). Here, specifically https://github.com/weaveworks/eksctl/pull/859/files#diff-316c11863e678a47a8959c72694d1f10R27 . @errordeveloper I figure this wasn't intentional?

[errordeveloper]

No, it definitely wasn't intentional.

[errordeveloper]

@2opremio just looking at this once again - the change was intentionally introduced in #1124, but some commands don't construct valid config when ran without a config file, and some don't support --config-file at all (see #1126).