Merge branch 'mariabdb' into 'master'

Mariabdb

See merge request hpc-team/ansible_cluster_in_a_box!232

roles/slurm-mysql-config/tasks/main.yml

+- name: "Copy slurm db tuning config"
+  template: src=slurm.cnf.j2 dest=/etc/my.cnf.d/slurm.cnf
+  become: true
+  become_user: root

roles/slurm-mysql-config/templates/slurm.cnf.j2

+[mysqld]
+innodb_buffer_pool_size=1024M
+innodb_log_file_size=256M
+innodb_lock_wait_timeout=900