Performance metrics

[mattgperry]

This PR introduces a Motion performance tracking API.

import { recordStats } from "motion/debug"

const report = recordStats()

animate(0, 100)

setTimeout(() => {
  const stats = report()
}, 100)

Reported stats take the form:

interface Summary {
    min: number
    max: number
    avg: number
}

interface Stats<T> {
    frameloop: {
        [key in FrameLoopStatNames]: Summary
    }
    animations: {
        mainThread: Summary
        waapi: Summary
        layout: Summary
    }
    layoutProjection: {
        nodes: Summary
        calculatedTargetDeltas: Summary
        calculatedProjections: Summary
    }
}