[Feature request] external download provider

[Ghost6798]

Checklist

• [x] I have searched for existing issues (open and closed) and confirmed this feature hasn't been requested before
• [x] I believe this feature request will benefit more than 10% of users, not just myself

Feature Description

instead of adding YTDLnis or seal adding what libretube has called external download provider this will let users chose what they wanna use if they chose nothing then the default will be picked hopefully legacy download this will not only make it easier for you but make the users happy

[Ghost6798]

Forgot to mention adding downloads to the main tabs would also be awesome but idk if its been asked before