MXS-2458: add template for Clustrix monitor tests

First implementation of Clustrix setup creation
TODO: move Clustrix installation to MDBCI

maxscale-system-test/testconnections.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "mariadb_nodes.h"
+#include "clustrix_nodes.h"
 #include "maxscales.h"
 #include "templates.h"
 #include <fcntl.h>
@@ -104,6 +105,8 @@ public:
      */
     Mariadb_nodes* repl;
 
+    Clustrix_nodes * clustrix;
+
     /**
      * @brief maxscales Maxscale object containing referebces to all Maxscale machines
      */
@@ -230,6 +233,11 @@ public:
      */
     bool no_galera;
 
+    /**
+     * @brief no_clustrix Do not check, restart and use Clustrix setup
+     */
+    bool no_clustrix;
+
     /**
      * @brief no_vm_revert If true tests do not revert VMs after the test even if test failed
      * (use it for debugging)