[Feature]: Multiple Format download

Prerequisites

• I have searched existing issues and discussions to ensure this feature hasn't been requested before
• I have read the feature request guidelines in the README
• I understand that MeTube development relies on community contributions and the maintainer is not likely to implement this feature
• I have considered if this feature should be implemented in yt-dlp instead of MeTube (if so, please report to yt-dlp repository)

Feature Description

I would like to select non-video formats of the same video to download in the same queue (presumably subject to the MAX_CONCURRENT_DOWNLOADS limit). My use case is watching a YouTube video in Jellyfin, complete with the original thumbnails and captions if available. But when selecting Format | Any, only the video file is downloaded in a format like .webm. Getting all three formats involves a surprising number of steps, especially for many single videos. Each step crossed out below is one that might be saved with multiple selection:

1. Paste the URL
2. Select 1080p in Quality and MP4 in Format
3. Click Download button
4. Wait for download to finish so other formats don't silently fail to queue
5. Paste the URL again because the field reset
6. Select Thumbnail in Format
7. Click Download button
8. Wait for the grayed out buttons to be clickable again
9. Paste the URL again
10. Select Captions in Format
11. Click Download button

Implementation Plan

No, I'm requesting this feature but cannot implement it

Additional Context

UI ideas

Some programs have dropdown menus that stay open. When the user clicks on one of their items, it get a checkmark and the user can continue selecting other items until clicking outside of the dropdown. In the MeTube Format dropdown, video formats are associated with multiple qualities while every other format only has "Best". To avoid suddenly hiding the video quality as other formats are selected, it might be simplest to only show video options in Quality. Finally, persisting these and other web UI settings across container restarts and even recreation would be helpful for users that prefer the same settings for most downloads.

Alternative

I'm not a developer and am new to yt-dlp. I have no idea if this can be implemented in YTDL_OPTIONS without being overridden by the web UI settings. But if I need to entirely bypass the web UI, I might as well learn yt-dlp and setup an inotify script to watch a text file of URLs instead.