Add into settings default line ending for new files

Add option into the Qt Creator settings option to configure what line
ending will the newly create files have.

Change-Id: I0fa67a54c78524dc943c01acb925c1bac1e47cc1
Fixes: QTCREATORBUG-3590
Reviewed-by: André Hartmann <aha_1980@gmx.de>
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/coreplugin/generatedfile.cpp

@@ -162,6 +162,7 @@ bool GeneratedFile::write(QString *errorMessage) const
 
     Utils::TextFileFormat format;
     format.codec = EditorManager::defaultTextCodec();
+    format.lineTerminationMode = EditorManager::defaultLineEnding();
     return format.writeFile(m_d->path, contents(), errorMessage);
 }