title: application cannot get the running AppImage path
body: <p>In my application, sometimes I need to find out the path of the application executable. I use <code>QApplication::applicationFilePath()</code> and it works fine. But when I distribute my application as AppImage on Linux, this breaks. It returns the path where the running AppImage was mounted, e.g. <code>/tmp/.mount_MyAppxyzabc/MyApp</code>. But I would need to get the path of the AppImage itself, e.g. <code>/home/vlad/MyApp/MyApp.AppImage</code>. Is this possible to obtain from inside the running application?</p>