citra_qt: load translation from resource

src/citra_qt/configuration/configure_general.h

@@ -19,6 +19,13 @@ public:
     ~ConfigureGeneral();
 
     void applyConfiguration();
+    void retranslateUi();
+
+private slots:
+    void onLanguageChanged(int index);
+
+signals:
+    void languageChanged(const QString& locale);
 
 private:
     void setConfiguration();