- Added pre-commit hook to lint backup shell script.

- Backup is now done by the OS user nobody and MySQL user backup.
- Backup script now outputs start, finish and error to stdout.
- Removed dependency on ca-store Ansible role.
- The MySQL user is added to the ssl group only if the group exists.
- Backup provisioninig is now optional depending on if the mysql_backup_password
  variables is defined.
- Moved most configuration to templates inside conf.d.
- Remote admin account is now optional depending on if the mysql_admin_password
  is defined.
- The mysql-server packges is reconfigured to reset root password if it's
  needed.