Add task organizer based task embedder

- Split TaskEmbedder into its current VirtualDisplay implementation
  and an implementation that uses task org to create and manage
  the task
- Use the task org embedder implementation in separate bubble task view
- Skip task org tasks from triggering task resizing
- Add task org callback for back press on task root if requested

Bug: 148977538
Test: atest CtsWindowManagerDeviceTestCases:ActivityViewTest
Test: atest WmTests:TaskOrganizerTests
Change-Id: Id422bb2547197c617f914ed7cf5085e02a1c3fb5