Sets up LifecycleOwner for shade.

For more info about the design, please see go/sysui-lifecycleowner.

Bug: 235402910
Test: includes unit tests for new components. Also verified manually. I
added a LifecycleObserver in KeyguardBottomAreaView, which is a view in
the view-hiearchy rooted under the shade window view. This observer saw
the correct lifecycle state when the lock-screen was showing, when the
device was unblocked with the notification shade fully retracted out of
the way and when the notification shade began to get expanded.

Change-Id: I009f0cecd3a65768660d51ef1642b65dc2ced9c2