Run MariaDB

This role deploys a standalone MariaDB using docker-compose.
Variables below configure MariaDB connection details.

**Role Variables**

.. zuul:rolevar:: mariadb_dbname

   The database to create.

.. zuul:rolevar:: mariadb_username

   The MariaDB user to make and connect with.

.. zuul:rolevar:: mariadb_password

   The password to set for ``mariadb_username``

.. zuul:rolevar:: mariadb_root_password

   The password to set for the root mariadb user.