Configure multiple group-level clusters
Problem to solve
Once group-level clusters are implemented a part of gitlab-ce#34758 (closed), only single-cluster configuration will be supported.
Organization often times need to create multiple clusters at the group level that may map to one or more environments.
(Include use cases, benefits, and/or goals)
Allow users to define multiple clusters at the group level.
What does success look like, and how can we measure that?
(If no way to measure success, link to an issue that will implement a way to measure this)