Refactor window handling code

Currently when we want to show/raise the window in reaction to the tray icon/notification being clicked etc we do this by emitting a signal on the controller.
This is connected to in main.qml, which does some things, then calls back to controller to do more things.

This is quite convoluted. Instead introduce a new class WindowController that is responsible for all things window, in particular showing/raising and config saving

src/runner.cpp

@@ -8,6 +8,7 @@
 #include "roomlistmodel.h"
 #include "roommanager.h"
 #include "runner.h"
+#include "windowcontroller.h"
 
 RemoteImage Runner::serializeImage(const QImage &image)
 {
@@ -90,5 +91,6 @@ void Runner::Run(const QString &id, const QString &actionId)
     }
 
     RoomManager::instance().enterRoom(room);
-    Q_EMIT Controller::instance().showWindow();
+
+    WindowController::instance().showAndRaiseWindow(QString());
 }