Refactor CProcessCtrl to start detached with or without console

QTBUG-53833 - which caused a console application to launch with a console
if it was started with QProcess::startDetached - is fixed in 5.8.0.
There were use cases for both options - with and without console -
but not offered by Qt API. Therefore CProcessCtrl is refactored  as a
wrapper to offer both options. If no console is required, it defaults to
QProcess::startDetached. Otherwise uses its own implementation.

refs #866

src/blackmisc/processctrl.h

@@ -30,7 +30,7 @@ namespace BlackMisc
         CProcessCtrl(QObject *parent = nullptr);
 
         //! Start a programm detached and without any console window
-        static bool startDetachedWithoutConsole(const QString &program, const QStringList &arguments);
+        static bool startDetached(const QString &program, const QStringList &arguments, bool withConsoleWindow);
     };
 } // ns