Utils: Make the second parameter to LayoutBuilder::attach() an enum

More explicit and more potential options (e.g. "treat grid as form")
than a bool.

Change-Id: I89413efe30410160c38b0e524ba64288dde2332e
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/cmakeprojectmanager/cmakebuildconfiguration.cpp

@@ -363,7 +363,7 @@ CMakeBuildSettingsWidget::CMakeBuildSettingsWidget(CMakeBuildSystem *bs) :
                 }
             }
         }.setSpacing(0)
-    }.attachTo(details, false);
+    }.attachTo(details, WithoutMargins);
 
     updateAdvancedCheckBox();
     setError(m_buildSystem->error());