Support other sources. Not only youtube

[agzam]

It's not going to be possible to easily extract subtitles from Netlfix or HBOmax (due to DRM). Not with yt-dlp anyway. But some other sources like Curiositystream and NebulaTV would let you extract subs with yt-dlp. Sometimes auth is required, and sometimes it can be skipped. Hypothetically, the package should work with Vimeo out of the box, but I have failed to find a single video with subtitles and the platform doesn't auto-generate any, so I couldn't test that. I tried tapping into vids on Coursera, but failed to figure out how to get yt-dlp to work with it. That's another non-youtube source that would be nice to have supported.

Alternatively (and perhaps easier to achieve) is to add an ability to supply any arbitrary args to yt-dlp executable. But that might be the opening of pandora's box since so many parameters may result in not generating the file(s) required for the package to show the buffer. But maybe that's what it should do - display the log of execution instead.