This works around an issue with RN's view reconciliation when the
root component has no background color defined.

It was handled inappropriately and some touch events were
intercepted unintentionally.

Continued work on Android

* Rename TopTabsLayout to TopTabsViewPager
* Pass ScrollEventListener from component
* Change ViewController.view to protected
* Don't keep ref to view in ComponentController
* Pull IReactView and ReactViewCreator to separate classes
* Ensure ToolBar.menu is created before clearing menu items
* Unmount react view before destroy
* Let TopTabsController set mediator in view visibility handling

* Initial overlay implementation on Android

* Move logic to touch delegate

* Implement dismiss Overlay

* Overlay e2e

* fix iOS e2e