Merge global settings and accounts into a pagedialog

Also split external tools into it's own page

gui/MainWindow.h

@@ -30,6 +30,7 @@ class QLabel;
 class MinecraftProcess;
 class ConsoleWindow;
 class BaseProfilerFactory;
+class GenericPageProvider;
 
 namespace Ui
 {
@@ -189,6 +190,8 @@ private:
 	QToolButton *changeIconButton;
 	QToolButton *newsLabel;
 
+	std::shared_ptr<GenericPageProvider> m_globalSettingsProvider;
+
 	InstancePtr m_selectedInstance;
 	QString m_currentInstIcon;