Address standalone kubelet config case

Also place in global vars and do not repeat the kube_*_config_dir
and kube_namespace vars for better code maintainability and UX.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

roles/network_plugin/flannel/tasks/main.yml

@@ -10,7 +10,7 @@
 - name: Flannel | Create flannel pod manifest
   template:
     src: flannel-pod.yml
-    dest: /etc/kubernetes/manifests/flannel-pod.manifest
+    dest: "{{kube_manifest_dir}}/flannel-pod.manifest"
   notify: Flannel | delete default docker bridge
 
 - name: Flannel | Wait for flannel subnet.env file presence