[feature] Option to add timestamped video bookmarks

[sebthom]

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

I'd suggest to add an option that allows adding bookmarks within videos.

Why do you want this feature?

This would be very handy when watching to long interviews/podcasts/documentaries that have some very valuable sections one want to be able to quickly rewatch.

Additional information

No response