Extractors

• [nrk] Improve series metadata extraction (#27473)

• [nrk] Extract subtitles

• [nrk] Fix age limit extraction
• [nrk] Improve video id extraction

• [nrk] Add support for podcasts (#27634, #27635)

• [nrk] Generalize and delegate all item extractors to nrk

• [nrk] Add support for mp3 formats

• [nrktv] Switch to playback endpoint
• [vvvvid] Fix season metadata extraction (#18130)
• [stitcher] Fix extraction (#20811, #27606)
• [acast] Fix extraction (#21444, #27612, #27613)

• [arcpublishing] Add support for arcpublishing.com (#2298, #9340, #17200)
• [sky] Add support for Sports News articles and Brighcove videos (#13054)
• [vvvvid] Extract akamai formats

• [vvvvid] Skip unplayable episodes (#27599)
• [yandexvideo] Fix extraction for Python 3.4