created first version of settingstab: Timeouts

scuffed prototype

To-Dos:
- make the UI look cleaner
- clean up copy&pasted coding

src/widgets/settingspages/AdvancedPage.hpp

@@ -8,6 +8,17 @@ class AdvancedPage : public SettingsPage
 {
 public:
     AdvancedPage();
+
+    void timeoutDurationChanged(QLineEdit &durationPerUnit, const QString &unit,
+                                QSpinBox &durationInSec,
+                                QStringSetting settingDurationInUnit);
+
+    void calculatedDurationChanged(const int durationInSec,
+                                   IntSetting settingDurationInSec);
+
+    void timeoutUnitChanged(const QString newUnit, QStringSetting settingUnit);
+
+private:
 };
 
 }  // namespace chatterino