MXS-2243_labels Maxscale system tests prepare environment by themselves

maxscale-system-test changed in order to control test environment by itself.
Every test checks which machines are running, compare with list of needed machines
and start new VMs is they are missing in the running machines list.
Tests are executiong MDBCI commands, MDBCI executable should be in the PATH

maxscale-system-test/labels_table.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <string>
+
+struct labels_table_t
+{
+    const char* test_label;
+    const char* mdbci_label;
+
+};
+
+const labels_table_t labels_table [] __attribute__((unused)) =
+{
+    {"REPL_BACKEND", "REPL_BACKEND"},
+    {"GALERA_BACKEND", "GALERA_BACKEND"},
+    {"TWO_MAXSCALES", "SECOND_MAXSCALE"},
+    {"COLUMNSTORE_BACKEND", "COLUMNSTORE_BACKEND"},
+};
+
+/**
+ * @brief get_mdbci_lables Finds all MDBCI labels which are needed by test
+ * Every test has a number of labels defined in the CMakeLists.txt,
+ * some of these lables defines which nodes (virtual machines) are needed
+ * for this particular test. Function finds such labels and forms labels string
+ * in the 'mdbci up' command format
+ * @param labels_string All lables from CMakeLists.txt
+ * @return Labels string in the 'mdbci up' --labels parameter format
+ */
+std::string get_mdbci_lables(const char * labels_string);