refactor: invert the last engine-to-UI dependencies

- NodeFactory's menu creation moves to UI-side widget/menu/factorymenu
  (the factory only exposes its node library read-only now)
- DiskManager's cache-settings dialog is created through a registered
  std::function handler (registered by Core at startup)
- OlivePluginInstance creates progress UIs through a
  PluginProgressReporter interface (Null fallback headless) and queries
  the active viewer through a provider callback, both registered by Core
- factory.h, diskmanager and pluginSupport no longer reference any
  widget//dialog//panel//window headers or classes

app/widget/toolbar/toolbar.cpp

@@ -27,8 +27,8 @@
 #include <QResizeEvent>
 #include <QVariant>
 
-#include "node/factory.h"
 #include "ui/icons/icons.h"
+#include "widget/menu/factorymenu.h"
 #include "widget/menu/menu.h"
 #include "widget/menu/menushared.h"
 
@@ -206,7 +206,7 @@ void Toolbar::add_button_clicked()
 
 void Toolbar::transition_button_clicked()
 {
-	Menu *m = NodeFactory::create_menu(this, false, Node::k_category_transition);
+	Menu *m = create_node_menu(this, false, Node::k_category_transition);
 
 	connect(m, &QMenu::triggered, this, &Toolbar::transition_menu_item_triggered);
 
@@ -217,7 +217,7 @@ void Toolbar::transition_button_clicked()
 
 void Toolbar::transition_menu_item_triggered(QAction *a)
 {
-	emit selected_transition_changed(NodeFactory::GetIDFromMenuAction(a));
+	emit selected_transition_changed(get_node_id_from_menu_action(a));
 }
 
 }