EditorSwitcherView class should be refactored

[JakMobius]

The EditorSwitcherView class is huge. This class handles the layout of the editors entirely: 2d-layout, 3d-layout, all transition animations and so on. At a minimum, the 2d and 3d layout should have been split into two different managers that would switch when needed.

And generally speaking, the original design with the 3d-layout switch has already been removed from Safari on iOS (but it is still used in the Mail application). It might be worth replacing it with a current one.