Wizards: Make the big wizards icons smaller

The feedback was clear: Icons were too big. This patch decreases
the sizes from 92x68 to 48x48. 48x48 should not be too big anymore,
and at the same time it should still allow to have an understandable
image.

Change-Id: I45a9f2214a43987ed60d2bd7527c025016dde745
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/coreplugin/dialogs/newdialog.cpp

@@ -47,7 +47,7 @@ Q_DECLARE_METATYPE(Core::IWizardFactory*)
 
 namespace {
 
-const int ICON_SIZE = 92;
+const int ICON_SIZE = 48;
 const char LAST_CATEGORY_KEY[] = "Core/NewDialog/LastCategory";
 const char LAST_PLATFORM_KEY[] = "Core/NewDialog/LastPlatform";