Create a ActiveRecord::Relation for all the projects that have a feature available
Follow up for discussion from !2279 (merged).
Some feature can be active on group-level (e.g. Contribution Analytics, Group Webhooks), but that doesn't mean they are active for all child projects. For example, when EE::ApplicationSetting#should_check_namespace_plan? is active, all EE features are active for public groups, but that doesn't mean the feature work for private descendant projects projects. Possibly, the situation is even more complicated, when subgroups under that public group have a namespace Plan active.
Therefore, a Finder (or something) should be built that returns all the descendant projects of a given group that have access to a given feature.
Until this issue is resolved, most Group-level EE features will not be active for public groups on GitLab.com.