message: Dock Cesium tabs in sensible places by default.
  Also open the main Cesium tab by default.
diff: #include "Cesium3DTiles/Tileset.h"
  #include "UnrealConversions.h"
  #include "CesiumIonRasterOverlay.h"
  +#include "LevelEditor.h"
  +#include "Framework/Docking/LayoutExtender.h"
  +#include "Framework/Docking/TabManager.h"
  IMPLEMENT_MODULE(FCesiumEditorModule, CesiumEditor)
  @@ -104,6 +107,14 @@ void FCesiumEditorModule::StartupModule()
  .SetDisplayName(FText::FromString(TEXT("Cesium ion Assets")))
  .SetTooltipText(FText::FromString(TEXT("Cesium ion Assets")))
  .SetIcon(FSlateIcon(TEXT("CesiumStyleSet"), TEXT("Cesium.MenuIcon")));
  +
  + FLevelEditorModule* pLevelEditorModule = FModuleManager::GetModulePtr<FLevelEditorModule>(FName(TEXT("LevelEditor")));
  + if (pLevelEditorModule) {
  + pLevelEditorModule->OnRegisterLayoutExtensions().AddLambda([](FLayoutExtender& extender) {
  + extender.ExtendLayout(FTabId("PlacementBrowser"), ELayoutExtensionPosition::After, FTabManager::FTab(FName("Cesium"), ETabState::OpenedTab));
  + extender.ExtendLayout(FTabId("OutputLog"), ELayoutExtensionPosition::Before, FTabManager::FTab(FName("CesiumIon"), ETabState::ClosedTab));
  + });
  + }
  }
  void FCesiumEditorModule::ShutdownModule()
  