Bring back MariaDB commit

We needed to sneak in a commit to master, but the MariaDB commit was
blocking the pipeline.

Revert "Revert "Replace MySQL with MariaDB""

This reverts commit 263bba3ae33c9d8cb4c1911b8b5e976fe785ecad.
Mariadb now used in mysql job

-Rename mysql job/template to mysql_placeholder
-Can now be deployed on existing environment without loss
of database

[finishes #71062108]