Move stream operator from AppEnum header

This PR will reduce the compile time of code using AppEnum. 

* AppEnum: Move QTextStream operator to avoid include of QTextStream
* Avoid use of iostream in cafAssert
rator to avoid include of QTextStream

Include file profiling shows that include of QTextStream is a performance issue. Create a non-templated base class for AppEnum. Implement the QTextStream operator for this interface.

Fwk/AppFwk/cafPdmScripting/cafPdmFieldScriptingCapability.h

@@ -45,6 +45,7 @@
 #include "cafPdmScriptIOMessages.h"
 
 #include <QIODevice>
+#include <QTextStream>
 
 #define CAF_PDM_InitScriptableField( field, keyword, default, uiName, ... )                          \
     {                                                                                                \