Split home stack into home and recents stack

Refactored functionality of home stack (HOME_STACK_ID) in the code
base to home stack and recents stack (RECENTS_STACK_ID). Also changed
function and variable names from homeStack to homeOrRecentsStack.

Differentiating home and recents stack will allow readablilty and
managing logic between home and recents stacks. For example, for
multi-window minimized dock state, the home and recents stacks can
be set to different rects where the home stack needs to be a fixed
large size while the recents stack is hidden and the dock stack is
animating to be minimized.

Fixes: 32839371
Test: ./run-test android.server.cts and manually tested split and
rotation
Change-Id: I7603359c2dc20e35924664178634eb761e0367a6