Moved entity interfaces into parent folder. Fixes #504

src/Entities/AccessTokenEntityInterface.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace League\OAuth2\Server\Entities;
+
+use League\OAuth2\Server\CryptKey;
+
+interface AccessTokenEntityInterface extends TokenInterface
+{
+    /**
+     * Generate a JWT from the access token
+     *
+     * @param \League\OAuth2\Server\CryptKey $privateKey
+     *
+     * @return string
+     */
+    public function convertToJWT(CryptKey $privateKey);
+}