Add tags

Add tags to allow more granular tasks filtering.
Add generator script for MD formatted tags found.
Add docs for tags how-to.

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

roles/kubernetes/node/tasks/main.yml

@@ -1,23 +1,26 @@
 ---
 - include: install.yml
+  tags: kubelet
 
 - include: nginx-proxy.yml
   when: is_kube_master == false and loadbalancer_apiserver_localhost|default(false)
+  tags: nginx
 
 - name: Write kubelet config file
   template: src=kubelet.j2 dest={{ kube_config_dir }}/kubelet.env backup=yes
-  notify:
-    - restart kubelet
+  notify: restart kubelet
+  tags: kubelet
 
 - name: write the kubecfg (auth) file for kubelet
   template: src=node-kubeconfig.yaml.j2 dest={{ kube_config_dir }}/node-kubeconfig.yaml backup=yes
-  notify:
-    - restart kubelet
+  notify: restart kubelet
+  tags: kubelet
 
 - name: Write proxy manifest
   template:
     src: manifests/kube-proxy.manifest.j2
     dest: "{{ kube_manifest_dir }}/kube-proxy.manifest"
+  tags: kube-proxy
 
 # reload-systemd
 - meta: flush_handlers
@@ -27,3 +30,4 @@
     name: kubelet
     enabled: yes
     state: started
+  tags: kubelet