Provision MySQL

Summary:
MariaDB has been selected as MySQL server flavour,
to get Cassandra, Aria and XtraDB.

FreeBSD servers with ZFS can benefit from a tweaked configuration
to avoid a duplicate InnoDB/ZFS cache, and to adjust block size.

For FreeBSD, we also require MariaDB 10.2 instead of 10.1.

Reference: https://cdn.oreillystatic.com/en/assets/1/event/21/Optimizing%20MySQL%20Performance%20with%20ZFS%20Presentation.pdf

Fixes T1306.

Test Plan: Deploy on Ysul and check ZFS partitions are populated

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1306

Differential Revision: https://devcentral.nasqueron.org/D1122