ChatOps Feature command doesn't work with Namespace objects

Problem

The ChatOps command to set a feature flag for a specific actor doesn't work (internal link) if the target is the full path of a user namespace. It works as expected when a group full path is passed in as option:

• /chatops run feature set --group=fabiopitino <feature_flag> true does not update anything.
• /chatops run feature set --group=gitlab-org <feature_flag> true update the FF correctly for the target group.

While it seems to work as expected, because a UserNamespace is not a Group, we allow a namespace to be used as actor in the code, as per our documentation.

# This is accepted
Feature.enabled?(:my_feature_flag, namespace, default_enabled: :yaml)

Solution

1. Allow the features API to take in input a namespace actor which is more generic than group and can cover both UserNamespace and Group - !79555 (merged)
2. Allow ChatOps to support --namespace= option when setting the actor. - gitlab-com/chatops!289 (merged)
3. Document the changes for the API and ChatOps !88443 (merged)