Add mariadb-server-galera package

A new mariadb-server-galera package is there for Deb and RPM packages for easy of installing a galera system and pulling its dependencies. Without galera, mariadb-server can be used. Those on Galera systems will need to install mariadb-server-galera explicity as an upgrade from previous version will result in galera dependencies being installed but not updated having a package dependency of MariaDB requiring them. Also the systemd service definations will no be galera capable for bootstrap or SST transfers without the mariadb-server-galera package. The wsrep_info plugin is installed by default with the mariadb-server-galera package. Use of the MYSQLD_OPTS as an environment variable for systemd services is deprecated and will be removed in a later release. Place configuration option in configuration files.