An easy to use wrapper around multipart fields for Actix web.
Use like:
```rust,ignore
pub fn upload(mut parts: awmp::Parts) -> Result
// Use remove to extract files by field name
// Persist the files to a directory of your choosing
let file_paths = parts.files.remove("upload").into_iter()
.map(|x| x.persist("/tmp") )
.collect::<Result<Vec<_>, _>>();
// ...
}