Add option to keep yt-dlp imported original files

[tilllt]

Describe the problem to be solved

We are using Peertube as an archive for problematic online information (hate-speech, propaganda etc.) which often will be deleted by the platforms originally published on shortly after. For accountability reasons we would like to store the originally downloaded file as "untouched" as possible, along with the maximum of original metadata: original URL on the respective Platform, account / username, description, title, hashtags etc.

Describe the solution you would like

The "keep original file" option already implemented for uploaded video files should be extended to imported video files as well.