Remove support for deploying OpenStack Monasca

Kolla Ansible is switching to OpenSearch and is dropping support for
deploying ElasticSearch. This is because the final OSS release of
ElasticSearch has exceeded its end of life.

Monasca is affected because it uses both Logstash and ElasticSearch.
Whilst it may continue to work with OpenSearch, Logstash remains an
issue.

In the absence of any renewed interest in the project, we remove
support for deploying it. This helps to reduce the complexity
of log processing configuration in Kolla Ansible, freeing up
development time.

Change-Id: I6fc7842bcda18e417a3fd21c11e28979a470f1cf