Fix duration time to consider playback rate

[vicente-higino]

• I agree to license my contribution under LGPL-3.0 or my contribution is from another project with a license compatible with LGPL-3.0

To test this pull request, follow the instructions in the wiki.

---

The duration of the video with skips now uses the playback rate to adjust the time.

Ex: 0:13 / 10:50 (9:16) @ 1x speed => 0:13 / 10:50 (4:38) @ 2x speed

[ajayyy]

I don't think this makes sense as a default. It could be an option though

[mchangrh]

I don't think this makes sense at all unless you correct youtube's current and end times to also align with the time without segments - in which case it would be better suited for a plugin/userscript to parse instead for uniformity across all durations.