add chapter about data repositories, and start work on perfomance chapter

implementation/16-data-repository/src/Http/Pipeline.php

@@ -0,0 +1,11 @@
+<?php declare(strict_types=1);
+
+namespace Lubian\NoFramework\Http;
+
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+
+interface Pipeline
+{
+    public function dispatch(ServerRequestInterface $request): ResponseInterface;
+}