Introduced the MasterController as part of working on loading catalogue information.

Need a central piece to manage the catalogue data per database to prevent loading
this multiple times. MasterController is now also used to enable reopening the
connection manager from a query window after the connection manager has been closed.

MasterController.h

@@ -0,0 +1,36 @@
+#ifndef MASTERCONTROLLER_H
+#define MASTERCONTROLLER_H
+
+#include <QObject>
+#include <map>
+
+class ConnectionConfig;
+class ConnectionListModel;
+class ConnectionManagerWindow;
+
+class MasterController : public QObject
+{
+	Q_OBJECT
+public:
+	explicit MasterController(QObject *parent = 0);
+	~MasterController();
+
+	void init();
+
+	ConnectionListModel *getConnectionListModel()
+	{
+		return m_connectionListModel;
+	}
+
+	void showConnectionManager();
+
+signals:
+
+public slots:
+
+private:
+	ConnectionListModel *m_connectionListModel = nullptr;
+	ConnectionManagerWindow *m_connectionManagerWindow = nullptr;
+};
+
+#endif // MASTERCONTROLLER_H