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/kubernetes-apps/network_plugin/canal/tasks/main.yaml

@@ -3,15 +3,15 @@
   kube:
     name: "canal-config"
     kubectl: "{{bin_dir}}/kubectl"
-    filename: "/etc/kubernetes/canal-config.yaml"
+    filename: "{{kube_config_dir}}/canal-config.yaml"
     resource: "configmap"
-    namespace: "kube-system"
+    namespace: "{{system_namespace}}"
 
 - name: Start flannel and calico-node
   run_once: true
   kube:
     name: "canal-node"
     kubectl: "{{bin_dir}}/kubectl"
-    filename: "/etc/kubernetes/canal-node.yaml"
+    filename: "{{kube_config_dir}}/canal-node.yaml"
     resource: "ds"
-    namespace: "kube-system"
+    namespace: "{{system_namespace}}"