Support promises and animated values for "expires" prop of v9 useTransition

Feature proposal for the new expires prop:

1. pass in a single animated value, or an array of animated values, so unmount will wait for these additional animated value(s) to rest, or if they're already at rest.
2. pass in a single Promise, or an array of Promises, so unmount will wait for the Promises to resolve.

A real-world use case for (1) above is when animating an interactive chart. Use a Spring value to animate the chart's x/y axis, while useTransition to manage the enter/leave/update of elements on the chart.

// Pass the animated value `x` to the `expires` prop of transition,
// so that the unmount event can wait for the X-axis animation to rest,
// instead of in the middle of X-axis animation.
const [{ x }, setAxis] = useSpring(() => { x: 100 });
const transition = useTransition(elements, { ...props, expires: [x] });

Originally posted by @guopengliang in https://github.com/react-spring/react-spring/pull/809#issuecomment-530700055

Start at useTransition and the expires option described here, then trace how useSpring animated values reach rest and how Promise resolution could be observed. Done means unmount waits for each supplied animated value to rest or each supplied Promise to resolve, including already-resting values and array inputs.