Kubernetes deployments on new clusters will now have
a separate namespace per project environment, instead
of sharing a single namespace for the project.
Behaviour of existing clusters is unchanged.
All new functionality is controlled by the
:kubernetes_namespace_per_environment feature flag,
which is safe to enable/disable at any time.
Now that Auto DevOps can run in a RBAC enabled cluster from
https://gitlab.com/gitlab-org/gitlab-ce/issues/51942, we can now remove
the FF.
As the flag only governed if UI elements would appear or not when
creating/adding existing clusters; the effect of removing the FF would
be that the checkbox to choose to enable RBAC clusters will now always
appear.
Remove FF stubs from specs
Improve spec context names
