Check unfree licenses (PeerTube API) and block or warn the upload

[arcstur]

PeerTube videos expose an API to get the license. We can use that to automatically reject uploads and fill the license template.

[arcstur]

Okay so this already happens through yt-dlp. I added free licenses in the PR #381

Now I guess it would be nice to also check unfree licenses and block or warn the user when trying to upload them. In the PR I only added templates for free licenses.