Make using sysctls a task instead of a concept (#6808)

Closes: #4505

_data/concepts.yml

@@ -43,7 +43,6 @@ toc:
     section:
     - docs/concepts/cluster-administration/network-plugins.md
     - docs/concepts/cluster-administration/device-plugins.md
-    - docs/concepts/cluster-administration/sysctl-cluster.md
   - docs/concepts/service-catalog/index.md
 
 - title: Containers

_data/tasks.yml

@@ -143,6 +143,7 @@ toc:
   - docs/tasks/administer-cluster/access-cluster-api.md
   - docs/tasks/administer-cluster/access-cluster-services.md
   - docs/tasks/administer-cluster/securing-a-cluster.md
+  - docs/tasks/administer-cluster/sysctl-cluster.md
   - docs/tasks/administer-cluster/encrypt-data.md
   - docs/tasks/administer-cluster/configure-upgrade-etcd.md
   - docs/tasks/administer-cluster/static-pod.md