Invidious, by design, has no images attached to chapters, in contrast to Piped.
Since the majority of videos with chapters don't have chapter-specific images and only use the videos' thumbnail, there is no difference here when compared to Piped's native thumbnail support.
Chapters have their own section is the settings. The users can decide if chapter thumbnails should be shown or not. Also they can decide to only show thumbnails if they are not the same.
The VideoDetailsView had to be modified, to avoid compiler type-checking errors.
When a user taps on a chapter, the pop now also shows the name of the chapter. The chapters are now marked in AppRedColor instead of orange.
This is based on PR #639
That one needs to be merged first before this one can go in.
