Add CCC relive to the "live" section

[yoshimo]

Checklist

• [x] I checked, but didn't find any duplicates (open OR closed) of this issue in the repo.
• [x] I have read the contribution guidelines given at https://github.com/TeamNewPipe/NewPipe/blob/HEAD/.github/CONTRIBUTING.md.
• [x] This issue contains only one feature request. I will open one issue for every feature I want to request.

Describe the feature you want

Between the presentation of a talk session and its proper release there is a window where the unprocessed stream dump +15m before and after it was held, gets listed under https://streaming.media.ccc.de//relive. So you can watch sessions you missed before they appear ,properly cut and with intro&outro, on media.ccc.de Would be nice if we had that section in the app as well, as it can take a while before events are processed and the videos released. Sometimes even multiple weeks.

[yoshimo]

https://live.alb.c3voc.de/relive/index.json http://cdn.c3voc.de/relive/index.json is the discovery link

https://live.alb.c3voc.de/relive/rc3/index.json is the current version for the rc3 events although past events are still there like https://live.alb.c3voc.de/relive/bigbrotherawards2020/index.json serving empty files