Resolve "Introduce PSR-4 autoloading"

Closes #12

classes/modules/UnknownModule.php

+<?php declare(strict_types=1);
+
+namespace uib\ub\loadspeakr\modules;
+
+use uib\ub\loadspeakr\HTTPStatus;
+
+/**
+ * Null result Loadspkr module.
+ *
+ * Used when unknown module is requested.
+ */
+final class UnknownModule implements ModuleInterface
+{
+
+    public function match($uri): void
+    {
+        HTTPStatus::send404($uri);
+    }
+
+    public function execute($params): void
+    {
+    }
+}