Feature request: parse the video thumbnail when it's added as an external media

When a media is played but not indexed on Android, we add it as an external media to keep track of some metadata (title, length, progress, ...).

It would be useful to add the thumbnail as well : for browsing and more important to display a valid thumb on the Android TV home (see vlc-android#2056 (closed))

Current behavior: the external media is created with an empty Thumbnail entry in the db

vlc_media.db (see Merlin l'enchanteur)