Upgrade various store methods to IAsyncEnumerable

PluralKit.Core/Utils.cs

@@ -669,4 +669,17 @@ namespace PluralKit
             EventId = Guid.NewGuid();
         }
     }
+
+    public static class ConnectionUtils
+    {
+        public static async IAsyncEnumerable<T> QueryStreamAsync<T>(this DbConnectionFactory connFactory, string sql, object param)
+        {
+            using var conn = await connFactory.Obtain();
+            
+            var reader = await conn.ExecuteReaderAsync(sql, param);
+            var parser = reader.GetRowParser<T>();
+            while (reader.Read())
+                yield return parser(reader); 
+        }
+    }
 }