feat: non-infinite silenceSpeed for "experimental" (cloning) algorithm

[WofWca]

Right now we're mostly performing seeks for this algorithm:

jumpcutter/src/entry-points/content/CloningController/CloningController.ts

Line 497 in fcda2b0

element.currentTime = seekTo;

But also sometimes we speed up, this can be taken as a basis:

jumpcutter/src/entry-points/content/CloningController/CloningController.ts

Lines 530 to 535 in fcda2b0

	if (farEnoughToSpeedUp) {
	// TODO what if `realTimeLeftUntilDestinationAtSilenceSpeed` is pretty big? Need to cancel this if
	// the user seeks to a sounded place.
	// May be other caveats.
	this._setSpeedAndLog(SpeedName.SILENCE);

My idea: we can make it work roughly the same way as seeking works right now. It's inefficient, but should work:
On every 'timeupdate' event, check if we're on a silent or on a sounded part, set speed accordingly, check when the current silence (loudness) period ends and setTimeout to switch speed at that time.

We also need to think how it's gonna be on the UI. Do we just set speed to infinite when the "silence speed" slider is at max value? Or do we make a separate checkbox?

Related #48