Simplify selecting a cover image

[DeD1rk]

What?

We should make it easy to select the cover image of an album.

Why?

Since we changed filenames to be randomized, paparazcie has a harder time selecting a cover image. They used to look up the number and then select it, but that's no longer possible (they can now only look up the filename and search for it).

How?

One option might be to somehow render the position of a photo in the cover image dropdown on the album admin, which would restore the previous behavior. But other options can also work, such as allowing the user to upload a file to use as cover image instead.

[tvanonna]

I think this issue has already been resolved, as when testing I am able to upload my own cover for albums.

[DeD1rk]

I see uploading one works kinda, but the problem is that the filenames in this dropdown are a pain