Merge "Support disabling Monasca alerting pipeline"

ansible/group_vars/all.yml

ansible/monasca_cleanup.yml

ansible/roles/monasca/defaults/main.yml

...les/monasca/templates/monasca-persister/persister.conf.j2

ansible/roles/storm/defaults/main.yml

ansible/roles/storm/tasks/cleanup.yml

...source/reference/logging-and-monitoring/monasca-guide.rst

...-disabling-monasca-alerting-service-92d49ead068447f8.yaml