refactored the settings dialog

src/widgets/settingspages/aboutpage.cpp

@@ -0,0 +1,13 @@
+#include "aboutpage.hpp"
+
+namespace chatterino {
+namespace widgets {
+namespace settingspages {
+
+AboutPage::AboutPage()
+    : SettingsPage("About", ":/images/about.svg")
+{
+}
+}  // namespace settingspages
+}  // namespace widgets
+}  // namespace chatterino