Add AB Loop

[absurdlylongusername]

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

We have loop, but no AB loop.
Add functionality to loop specific section of the video by specifying start and end time like you can do with most music players.

Why do you want this feature?

Convenience.

Additional information

Perhaps related or has similar solution: #8916