Payouts finish (#470)

* Almost done

* More work on midas

* Finish payouts backend

* Update Cargo.lock

* Run fmt + prepare

src/file_hosting/s3_host.rs

@@ -21,7 +21,7 @@ impl S3Host {
         access_token: &str,
         secret: &str,
     ) -> Result<S3Host, FileHostingError> {
-        let mut bucket = Bucket::new(
+        let bucket = Bucket::new(
             bucket_name,
             if bucket_region == "r2" {
                 Region::R2 {