Debugger: Export DebuggerManager and DebuggerStartParameters.

For device debugging. Move both from namespace
Debugger::Internal to Debugger, export them, give
DebuggerManager a static instance().

src/plugins/debugger/debuggeroutputwindow.cpp

@@ -55,6 +55,7 @@ using namespace Find;
 
 #endif // GDBDEBUGGERLEAN
 
+using namespace Debugger;
 using namespace Debugger::Internal;
 
 static QChar charForChannel(int channel)