Prepare Folder for new Folder animation implementation.

Refactored animator logic to separate methods, so that it is easier
to swap out implementation with the LAUNCHER3_NEW_FOLDER_ANIMATION flag.

ie.

AnimatorSet anim = LAUNCHER3_NEW_FOLDER_ANIMATION
    ? getNewOpeningAnimatorSet()
    : getOpeningAnimatorSet();

Bug: 35064148
Change-Id: I32a646aaed5081438d7a733dc3e7cceb484998ab