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/debuggerconstants.h

@@ -60,8 +60,6 @@ namespace Internal {
 }
 } // namespace Constants
 
-namespace Internal {
-
 enum DebuggerState
 {
     DebuggerNotReady,          // Debugger not started
@@ -118,7 +116,6 @@ enum LogChannel
     LogMisc    
 };
 
-} // namespace Internal
 } // namespace Debugger
 
 #endif // DEBUGGERCONSTANTS_H