Nim: Fix handling of project settings

Removes unused duplicate of nim specific project settings
and uses the nimble specific project settings additionally
inside nimble projects.

Change-Id: Ibbda76ab41538a0ebdf0a395503c519fcac93460
Reviewed-by: Filippo Cucchetto <filippocucchetto@gmail.com>
Reviewed-by: hjk <hjk@qt.io>

src/plugins/nim/project/nimbuildsystem.h

@@ -92,9 +92,6 @@ public:
     void triggerParsing() override;
 
 protected:
-    void loadSettings();
-    void saveSettings();
-
     ParseGuard m_guard;
     NimProjectScanner m_projectScanner;
 };