Synced from Eclipse Che issue

https://github.com/eclipse/che/issues/21582

Is your enhancement related to a problem? Please describe

In some cases administrators want to pre-create their namespaces and don't want to have Eclispe Che to automatically create them.

Describe the solution you'd like

Add a new property in CheCluster CR:

spec:
   components
   containerRegistry
   devEnvironments:
     defaultNamespace:
+      autoProvision: true   # <= true by default
       template
   networking

If spec.devEnvironments.defaultNamespace.disabled: true then Eclispe Che should not create namespaces if it doesn't exist. Eclispe Che should fail to start the workspace if the namespace doesn't exist:

⚠️
You are allowed to start a workspace as there is no Kubernetes Namespace assigned
to user <username> and the automatic creation of Namespaces is disabled in Che (
CheCluster spec.devEnvironments.defaultNamespace.autoProvision is set to false).

Read the documentation to create Namespaces in advance or contact your administrator to fix that.

Current workaround

To disable the automatic creation of users namespaces:

spec:
  components:
    cheServer:
      extraProperties:
        CHE_INFRA_KUBERNETES_NAMESPACE_CREATION__ALLOWED: 'false'

Release Notes Text

A new field in CheCluster has been added to avoid that users namespaces get created automatically. If devEnvironments.defaultNamespace.autoProvision is set to false and a user doesn't have a Che namespace, workspace creation will fail. autoProvision is set to true by default.