Unified "simplification" to ASCII only for text messages

Based on the codepage discussion of text messages

* in text message value object still store the unicode string
* the text is only "cleaned" up and Qt "simplified" (do not confuse with conversion to ASCII)
* only place where we simplify to ASCII only is
** in VATLIB
** or the utility

src/blackmisc/network/textmessage.h

@@ -85,6 +85,9 @@ namespace BlackMisc
             //! Get message
             const QString &getMessage() const { return m_message; }
 
+            //! Get ASCII only message
+            QString getAsciiOnlyMessage() const;
+
             //! Empty message
             bool isEmpty() const { return m_message.isEmpty(); }