Android Recents implementation for low ram devices

For now the implementation is set behind the ActivityManager flag if the
device has low memory.

This implementation has a linear list of tasks and less functionality
such as removing split screen and reducing the amount of tasks shown to
9. For more information please check out the bug.

Bug: 62251652
Test: manual
Change-Id: I8e0a822a865089df1e8bef55ca61ed30978748d0