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/download/tasks/main.yml

@@ -45,6 +45,7 @@
 
 - set_fact:
     download_delegate: "{% if download_localhost %}localhost{% else %}{{groups['kube-master'][0]}}{% endif %}"
+  tags: facts
 
 - name: Create dest directory for saved/loaded container images
   file: path="{{local_release_dir}}/containers" state=directory recurse=yes mode=0755 owner={{ansible_ssh_user|default(ansible_user_id)}}
@@ -78,6 +79,7 @@
 
 - set_fact:
     fname: "{{local_release_dir}}/containers/{{download.repo|regex_replace('/|\0|:', '_')}}:{{download.tag|regex_replace('/|\0|:', '_')}}.tar"
+  tags: facts
 
 - name: "Set default value for 'container_changed' to false"
   set_fact:
@@ -89,6 +91,7 @@
   when: "{{ download.enabled|bool and download.container|bool }}"
   delegate_to: "{{ download_delegate if download_run_once|bool else inventory_hostname }}"
   run_once: "{{ download_run_once|bool }}"
+  tags: facts
 
 - name: Stat saved container image
   stat: path="{{fname}}"