gallery-dl must use same filename convesion / structure for instagram stories as instaloader for user convenience

[estatistics]

gallery-dl produces names like "3340025270185039243_3340025264396894920.jpg" but instaloader produces names like "2024-04-01_11-58-43_UTC.jpg".

So, when there are times that instaloader is broken, i try to use gallery -dl but name convention is killing user-experience and convenience.

So, i propose to use same filename structure as instaloader for best user-experience.

[kattjevfel]

or users of instaloader can just change the filename template of gallery-dl to that, and leave the rest of us alone.

[mikf]

-f "{date:%Y-%m-%d_%H-%M-%S}_UTC_{media_id}.{extension}"

Files in posts with multiple photos can have the same date (for example https://www.instagram.com/p/BoHk1haB5tM/), hence {media_id}