Support 'posts' for YouTube

Checklist

• I am aware that this issue is being opened for the NewPipe Extractor, NOT the app, and my feature request will be dismissed otherwise.
• I made sure that there are no existing issues - open or closed - which I could contribute my information to.
• 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

YouTube channels can make posts, this is not supported by the extractor yet. And can not be displayed in apps like NewPipe and LibreTube as a result.

Why do you want this feature?

To be able to view posts from channels.

Additional information

https://support.google.com/youtube/answer/9409631?hl=en