Add support for Newgrounds audios and videos

[HGStyle]

Hi, I would really like (and probably not only me) to have an app for watching or listening to Newgrounds videos or audios, since it has no app for Android (iOS too I think, but I haven't checked). Newgrounds not having any protection (no Widevine, etc... by example the link to the direct audio file is actually returned directly in the HTML player of it) I think it would be very easy to add it into NewPipe. Also, it is present in YouTube-DL and its forks, so if you need some help, you can read its YouTube-DL extractor, even if it should be easy since its mostly just webscraping. Thanks ! [Ok, I know NewPipe is being rewritten and new features aren't gonna be added now, but since its a different GitHub repository, I'm trying anyways...]