UI: Add intro startup page (windows)

Allows the ability to show a web page via CEF to the users on startup to
present and announce new features.

UI/win-update/win-update.hpp

@@ -21,3 +21,15 @@ private slots:
 public:
 	AutoUpdateThread(bool manualUpdate_) : manualUpdate(manualUpdate_) {}
 };
+
+class WhatsNewInfoThread : public QThread {
+	Q_OBJECT
+
+	virtual void run() override;
+
+signals:
+	void Result(const QString &text);
+
+public:
+	inline WhatsNewInfoThread() {}
+};