[moveonly] Extract HelpRequested to dry up the help options testing

This ensures consistency across interfaces and makes the version handling more clear.

src/util.h

@@ -313,6 +313,11 @@ private:
 
 extern ArgsManager gArgs;
 
+/**
+ * @return true if help has been requested via a command-line arg
+ */
+bool HelpRequested(const ArgsManager& args);
+
 /**
  * Format a string to be used as group of options in help messages
  *