[Feature] Add chapters navigation buttons

[Monoxide8969]

At the current time, users can only jump to the start of a chapter. It's fine for normal chapters, but a bit cumbersome with nested ones, like in this case:

Here we have a parent chapter with some smaller, occasional child chapters. Those child chapters do not have anything in between them, because it would only be a repetition of the parent chapter.
The problem here is that the highligthed chapters are something only a fraction of the users are interested in, and thus it would be more convenient to skip them, not to skip to them.
Yeah, one could forcefully add chapters in between them, but I feel like it's an unnecessary extra step that would only add weight to the database.

I think a better solution would be to add something like a "Skip to the end of chapter" button (badly drawn in the image on top).

And since we're here, it would also be appreciated some kind of quick navigation in the video player (badly drawn in the image on top, again). A bit of thought should be go in this one, as too many buttons could easily make the UI messier than it needs to be. Maybe make it appear when hovering on the chapter name (?)

[ajayyy]

There are currently the next chapter and previous chapter hotkeys

[Monoxide8969]

My bad, I did not see them. Amazing that that's already implemented and I will surely use them now that I know. I still think it would be worth to add a UI implementation though.