Allow hiding/graying out watched videos in the channel view

[HFPasfho]

Checklist

• I made sure that there are no existing issues - open or closed - which I could contribute my information to.
• I have read the FAQ and my problem isn't listed.
• I'm aware that this is a request for NewPipe itself and that requests for adding a new service need to be made at NewPipeExtractor.
• I have taken the time to fill in all the required details. I understand that the feature request will be dismissed otherwise.
• This issue contains only one feature request.
• I have read and understood the contribution guidelines.

Feature description

Please add an option to hide (like in what's new tab) or gray out (or collapse or something more distinct than the thin red bar) watched videos in the channel view.

Why do you want this feature?

Current indication of thin red bar is often hard to notice especially when most videos on the list already have this bar. Also flashy youtube thumbnails make it harder to see.

Additional information

Since current solution is probably fine for the majority of users this option could be added to accessibility options.