[3/3] Introduce a new spring-based animation.

This is meant to be used for animations that have a starting velocity
(e.g. gesture nav, predictive back), but it can in principle be used
interchangeably with the interpolator-based animation that we've been
using so far.

Bug: 323863002
Flag: com.android.systemui.shared.return_animation_framework_library
Test: atest TransitionAnimatorTest
Change-Id: I5b22b2b8ef52f248583d71c5ee4d113b6993baae