Implement /ignore and /unignore commands

Simplify authorized network requests for Twitch V5 api
add onShow virtual function to settings pages if they need to be refreshed when shown
Actually ignoring messages from ignored users is still not implemented

Working on #247

src/widgets/settingspages/settingspage.hpp

@@ -28,6 +28,10 @@ public:
     QLineEdit *createLineEdit(pajlada::Settings::Setting<QString> &setting);
     QSpinBox *createSpinBox(pajlada::Settings::Setting<int> &setting, int min = 0, int max = 2500);
 
+    virtual void onShow()
+    {
+    }
+
 protected:
     QString name;
     QString iconResource;