This enables terminals for group and project level clusters.
Previously there was no way to determine which project (and
therefore kubernetes namespace) to connect to, moving this
logic onto Environment means the assoicated project can be
used to look up the correct namespace.
We are deprecating this service in favor of instance wide clusters.
Therefore we removed some code that is not anymore needed for a
readonly cluster and also we added some flags to allow for this
deprecation. These flags are to be removed in the next release when
we finally completelly remove KubernetesService.
Tiger