Add SVG icons for five Std Tool commands

This commit adds SVG files with icons for these commands. Also, it makes the necessary changes on CommandStd.cpp, CommandDoc.cpp, CommandView.cpp and resource.qrc files. 
Forum Discussion: https://forum.freecadweb.org/viewtopic.php?f=34&t=51502&start=10

src/Gui/CommandDoc.cpp

@@ -384,6 +384,7 @@ StdCmdDependencyGraph::StdCmdDependencyGraph()
     sStatusTip    = QT_TR_NOOP("Show the dependency graph of the objects in the active document");
     sWhatsThis    = "Std_DependencyGraph";
     eType         = 0;
+    sPixmap       = "Std_DependencyGraph";
 }
 
 void StdCmdDependencyGraph::activated(int iMsg)
@@ -658,6 +659,7 @@ StdCmdProjectUtil::StdCmdProjectUtil()
     sMenuText     = QT_TR_NOOP("Project utility...");
     sToolTipText  = QT_TR_NOOP("Utility to extract or create project files");
     sStatusTip    = QT_TR_NOOP("Utility to extract or create project files");
+    sPixmap       = "Std_ProjectUtil";
 }
 
 void StdCmdProjectUtil::activated(int iMsg)

src/Gui/CommandStd.cpp

@@ -343,7 +343,7 @@ StdCmdDlgParameter::StdCmdDlgParameter()
   sToolTipText  = QT_TR_NOOP("Opens a Dialog to edit the parameters");
   sWhatsThis    = "Std_DlgParameter";
   sStatusTip    = QT_TR_NOOP("Opens a Dialog to edit the parameters");
-  //sPixmap     = "settings";
+  sPixmap       = "Std_DlgParameter";
   eType         = 0;
 }
 

src/Gui/CommandView.cpp

@@ -3009,6 +3009,7 @@ StdCmdSceneInspector::StdCmdSceneInspector()
     sWhatsThis    = "Std_SceneInspector";
     sStatusTip    = QT_TR_NOOP("Scene inspector");
     eType         = Alter3DView;
+    sPixmap       = "Std_SceneInspector";
 }
 
 void StdCmdSceneInspector::activated(int iMsg)
@@ -3067,6 +3068,7 @@ StdCmdDemoMode::StdCmdDemoMode()
     sWhatsThis    = "Std_DemoMode";
     sStatusTip    = QT_TR_NOOP("View turntable");
     eType         = Alter3DView;
+    sPixmap       = "Std_DemoMode";
 }
 
 void StdCmdDemoMode::activated(int iMsg)