CI: Add MariaDB support (i.e. let integration tests run using MariaDB as a server)

[Andersson007]

SUMMARY

As there are issues specific to MariaDB reported and our fixes / features can affect MariaDB users, we need to have MariaDB in CI

Related files:

• .github/workflows/ansible-test-plugins.yml
• tests/integration/targets/setup_mysql/*

There's also currently not used role https://github.com/ansible-collections/community.mysql/tree/main/tests/integration/old_mariadb_replication that were used when the collection's content lived in ansible/ansible (might be helpful)

ISSUE TYPE

• Feature Idea