Load and draw Recent/Running tasks that aren't in Hotseat

- Re-support GroupTask as a tag on TaskbarView BubbleTextViews
- Can tap to launch (startActivityFromRecents) or drag and drop
- Move divider when enable_recents_in_taskbar is true

Behavior:
- While in Desktop mode, all open tasks show up in TaskbarView,
  either in the Hotseat section or the Running apps section
  past the divider. Each one also has a running line indicator.
- While in Fullscreen mode, up to 2 Recent apps that are not
  part of Hotseat will be added to the right of the divider.

Flag: com.android.launcher3.enable_recents_in_taskbar
Test: TaskbarRecentAppsControllerTest
Bug: 315354060
Change-Id: I2e2870cca434b51f276a701860edb32069109159