Call Grafana APIs only once

In multinode deployments creating default Grafana organization failed,
because Ansible attempted to call Grafana API in the context of each
host in the inventory. After creating organization via the first host,
subsequent attempts via the remaining hosts failed due to already
existing organization. This change enforces creating default
organization only once.

Other tasks using Grafana API have been enforced to be ran only once as
well.

Change-Id: I3a93a719b3c9b4e55ab226d3b22d571d9a0f489d
Signed-off-by: Bartosz Zurkowski <b.zurkowski@samsung.com>

ansible/roles/monasca/tasks/post_config.yml

@@ -21,6 +21,7 @@
     password: '{{ monasca_grafana_admin_password }}'
     return_content: true
     force_basic_auth: true
+  run_once: True
   register: monasca_grafana_orgs
 
 - name: Create default control plane organisation if it doesn't exist
@@ -33,6 +34,7 @@
     body:
       name: '{{ monasca_grafana_control_plane_org }}'
     force_basic_auth: true
+  run_once: True
   when: monasca_grafana_control_plane_org not in monasca_grafana_orgs.json|map(attribute='name')|unique
 
 - name: Lookup Monasca Grafana control plane organisation ID
@@ -43,6 +45,7 @@
     password: '{{ monasca_grafana_admin_password }}'
     return_content: true
     force_basic_auth: true
+  run_once: True
   register: monasca_grafana_conf_org
 
 - name: Add {{ monasca_grafana_admin_username }} user to control plane organisation
@@ -70,6 +73,7 @@
     user: '{{ monasca_grafana_admin_username }}'
     password: '{{ monasca_grafana_admin_password }}'
     force_basic_auth: true
+  run_once: True
 
 - name: Enable Monasca Grafana datasource for control plane organisation
   uri: