Revise cluster management task

After removing the sections of the page that are not in line with the
content guide, there is little left.

Edit pages that link to removed task to no longer link there.
Redirect using 302 status so that there is a future opportunity to reinstate
the page or something like it.

- Avoid links to removed cluster management task
- Broaden applicability of “Safely Drain A Node”
- Add (stub) cluster upgrade task page
- Add a basic page about upgrading your cluster.
- Add a task page about enabling or disabling HTTP APIs

content/en/docs/concepts/architecture/controller.md

@@ -92,9 +92,8 @@ Controllers that interact with external state find their desired state from
 the API server, then communicate directly with an external system to bring
 the current state closer in line.
 
-(There actually is a controller that horizontally scales the
-nodes in your cluster. See
-[Cluster autoscaling](/docs/tasks/administer-cluster/cluster-management/#cluster-autoscaling)).
+(There actually is a [controller](https://github.com/kubernetes/autoscaler/)
+that horizontally scales the nodes in your cluster.)
 
 The important point here is that the controller makes some change to bring about
 your desired state, and then reports current state back to your cluster's API server.

content/en/docs/concepts/architecture/nodes.md

@@ -338,5 +338,4 @@ for more information.
 * Read the [Node](https://git.k8s.io/community/contributors/design-proposals/architecture/architecture.md#the-kubernetes-node)
   section of the architecture design document.
 * Read about [taints and tolerations](/docs/concepts/scheduling-eviction/taint-and-toleration/).
-* Read about [cluster autoscaling](/docs/tasks/administer-cluster/cluster-management/#cluster-autoscaling).
 

content/en/docs/concepts/cluster-administration/_index.md

@@ -39,8 +39,6 @@ Before choosing a guide, here are some considerations:
 
 ## Managing a cluster
 
-* [Managing a cluster](/docs/tasks/administer-cluster/cluster-management/) describes several topics related to the lifecycle of a cluster: creating a new cluster, upgrading your cluster's master and worker nodes, performing node maintenance (e.g. kernel upgrades), and upgrading the Kubernetes API version of a running cluster.
-
 * Learn how to [manage nodes](/docs/concepts/architecture/nodes/).
 
 * Learn how to set up and manage the [resource quota](/docs/concepts/policy/resource-quotas/) for shared clusters.

content/en/docs/concepts/configuration/pod-priority-preemption.md

@@ -321,9 +321,7 @@ Pod may be created that fits on the same Node. In this case, the scheduler will
 schedule the higher priority Pod instead of the preemptor.
 
 This is expected behavior: the Pod with the higher priority should take the place
-of a Pod with a lower priority. Other controller actions, such as
-[cluster autoscaling](/docs/tasks/administer-cluster/cluster-management/#cluster-autoscaling),
-may eventually provide capacity to schedule the pending Pods.
+of a Pod with a lower priority.
 
 ### Higher priority Pods are preempted before lower priority pods