matomo: add role matomo. Service supports external plugins and Tag Manager
containers now. Migration of older Matomo installations is done
automatically (PL-131353).
Fix IPv6 networking after first boot by re-enabling automatic link-local
address generation. This problem led to confusing networking problems with
new machines which went away after the first reboot (PL-130011).
Add opensearch and opensearch_dashboards roles, version 2.6.0. They are
intended to replace Elasticsearch/Kibana 7.10.2 but the roles should only
be used for new installations right now. We will provide a migration path
from ES to OpenSearch later (PL-130611).