try to index media immediately on import

Since indexing is supplemental, it can be made a background task that can occur
at more or less any time. So we run it as soon as possible.

app/project/projectloadmanager.cpp

@@ -46,5 +46,5 @@ void ProjectLoadManager::Action()
     project_file.close();
   }
 
-  emit Finished();
+  emit Succeeeded();
 }