Recompilation speedup: use generic types in @spec in Upload.Filter
A similar compromise to !3434 (merged) and !3435 (merged) - taking structs out of typespecs in favor of the generic struct().
The hard way to solve this problem would be to make Pleroma.Upload ONLY be the struct, and split all functions into a separate Pleroma.Uploads (plural) module. But short of that, this is an easier way to reach 0 cycles.
Gets rid of a cycle and shrinks others: https://www.diffchecker.com/6q6CpYJK
