Core/Utils: Migrate further to Utils::Id

The coreplugin/id.h header is kept for downstream for now.

Change-Id: I8c44590f7b988b3770ecdc177c40783e12353e66
(cherry picked from commit 430a33dcd9)
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/coreplugin/basefilewizardfactory.cpp

@@ -45,6 +45,8 @@
 
 enum { debugWizard = 0 };
 
+using namespace Utils;
+
 namespace Core {
 
 static int indexOfFile(const GeneratedFiles &f, const QString &path)