* stricter youtubedl format selectors
make sure selectors avoid av1, and otherwise match as closely to the
maximum resolution enabled for transcoding
* add support for merge formats in youtubedl
* avoid vp9.2 in youtubedl to avoid any HDR
* move getEnabledResolutions, safer replace of imported extension
* add test for youtube-dl selectors
Fix weird behaviour with some web browsers. Don't really know if it's a
ffmpeg bug, a safari bug or a peertube bug, but forcing transcoding
seems to fix this playback bug
* Add video file metadata via ffprobe
* Federate video file metadata
* Add tests for file metadata generation
* Complete tests for videoFile metadata federation
* Lint migration and video-file for metadata
* Objectify metadata from getter in ffmpeg-utils
* Add metadataUrl to all videoFiles
* Simplify metadata API middleware
* Load playlist in videoFile when requesting metadata
This patch adds an audio-only option to PeerTube by means of a new transcoding configuration which creates mp4 files which only contain an audio stream. This new transcoder has a resolution of '0' and is presented in the preferences and in the player resolution menu as 'Audio-only' (localised). When playing such streams the player shows the file thumbnail as background and disables controls autohide.
Audio-only files can be shared and streamed just like any other file. They can be downloaded as well, the resulting file will be an mp4 container with a single audio stream.
This patch is a proof of concept to show the feasibility of 'true' audio-only support. There are better ways of doing this which also enable multiple audio streams for a given video stream (e.g. DASH) but as this would entail a fundamental change in the way PeerTube works it is a bridge too far for a simple proof of concept.