Support cover art in COVERART field in addition to METADATA_BLOCK_PICTURE field for ogg files

Right now, api/funkwhale_api/music/metadata.py looks for picture data in ogg files only in the metadata_block_picture section. While unofficial and depricated, some old ogg files store their cover art in the coverart section instead. See https://wiki.xiph.org/VorbisComment#Unofficial_COVERART_field_(deprecated)

It would be great if funkwhale could still use these images without having to mass convert old ogg files.

Related, documentation at https://docs.funkwhale.audio/administrator/import.html indicates cover art is only supported for mp3 and flac files, but clearly it works for ogg files that follow the standard, and it looks like mp4 and maybe additional formats?

added Area::Backend Component::Import Status::Draft Type::New feature labels

If you add tests to your mr we can merge it, has you can see in the test folder in tests/music we have very light audio tests files, you could add one that fits your description to build tests

thanks for contributing ! :D

mentioned in merge request !2862 (merged)

I've created a separate PR with just this change, including a test file.

mentioned in commit 830b0a48

closed with merge request !2862 (merged)