Add an indicator in the title bar if Streamer Mode is active (#4410)

src/widgets/helper/SettingsDialogTab.hpp

@@ -15,6 +15,7 @@ class SettingsDialog;
 
 enum class SettingsTabId {
     None,
+    General,
     Accounts,
     Moderation,
 };

src/widgets/helper/TitlebarButton.hpp

@@ -11,7 +11,8 @@ enum class TitleBarButtonStyle {
     Unmaximize = 4,
     Close = 8,
     User = 16,
-    Settings = 32
+    Settings = 32,
+    StreamerMode = 64,
 };
 
 class TitleBarButton : public Button