Add "Safe mode" which temporarily disables configs and addons (#16858)

* Add safe-mode which starts freecad in a clean environment

* Integrate safe-mode

* Show "(Safe Mode)" in main window title

* Show safe mode info when safe mode is started

* Created Safe Mode Icon

* Use new icon

* Add PreCompiled.h

* Add exports for windows

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Co-authored-by: Gabriel <gaz082@gmail.com>

src/Gui/Workbench.cpp

@@ -761,7 +761,8 @@ MenuItem* StdWorkbench::setupMenuBar() const
     *help << "Std_OnlineHelp" << "Std_FreeCADWebsite" << "Std_FreeCADDonation"
           << "Std_FreeCADUserHub" << "Std_FreeCADPowerUserHub"
           << "Std_PythonHelp" << "Std_FreeCADForum" << "Std_FreeCADFAQ"
-          << "Std_ReportBug" << "Std_About" << "Std_WhatsThis";
+          << "Std_ReportBug" << "Std_About" << "Std_WhatsThis"
+          << "Std_RestartInSafeMode";
 
     return menuBar;
 }