server/minecraft/service: Added sending warning to players about restart

roles/server/minecraft/templates/minecraft.service

@@ -20,6 +20,8 @@ ReadOnlyDirectories={{ installation_directory }}
 ReadWriteDirectories={{ data_directory }}
 WorkingDirectory={{ data_directory }}
 ExecStart={{ launch_script }}
+ExecStop={{ remote_control_script }} "say Server will be restarted in 5 seconds"
+ExecStop=/usr/bin/sleep 5
 ExecStop={{ remote_control_script }} stop
 ExecStop=/bin/bash -c "while ps -p $MAINPID > /dev/null; do /bin/sleep 1; done"