r/k8s-worker: Install iSCSI/NFS client tools

We don't want the iSCSI and NFS client tools to be installed on control
plane nodes.  Let's move this task to the _k8s-worker_ role so it will
only apply to worker nodes.

roles/kubelet/tasks/main.yml

@@ -112,16 +112,3 @@
     enabled: true
   tags:
   - service
-
-- name: ensure iscsi socket is enabled
-  systemd:
-    name: iscsid.socket
-    enabled: true
-  tags:
-  - service
-- name: ensure iscsi socket is active
-  systemd:
-    name: iscsid.socket
-    state: started
-  tags:
-  - service