Debugger: Move DebugInfoTask handling to plugin

This does not involve the engine (currently).

Task-number: QTCREATORBUG-19994
Change-Id: I07a628580bf99c988eb0df165d649d5cc0869c0d
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

src/plugins/debugger/debuggercore.h

@@ -124,5 +124,7 @@ QAction *addCheckableAction(QMenu *menu, const QString &display, bool on, bool c
 // Qt's various build paths for unpatched versions
 QStringList qtBuildPaths();
 
+void addDebugInfoTask(unsigned id, const QString &cmd);
+
 } // namespace Internal
 } // namespace Debugger