Add endpoint to download multidata directly

ALttPRandomizer/Service/SeedService.cs

@@ -127,5 +127,9 @@
 
             return result;
         }
+
+        public async Task<BinaryData?> GetMultidata(string multiId) {
+            return await this.AzureStorage.GetFile($"{multiId}/multidata");
+        }
     }
 }