[Slim] Add ApiKey and OAuth authentication middleware (#1207)

* [Slim] Add fork of token middleware

This commit will be dropped, when official repo approves submitted PRs.
Right now it's for test purposes only.

* [Slim] Adds token middleware to template

* [Slim] Move auth implementation to external classes

* [Slim] Update readme

* [Slim] Add config example

* [Slim] Remove deprecated package

Considered to use dyorg/slim-token-authentication for all authentication
schemes. User needs to decode and parse Basic token himself, but it's
pretty simple task and there are many code examples in
the web. Most of time solution is two lines of code.

* [Slim] Format phpdoc comments

I've changed PHP version to 7 and updated comments to follow  main
recommendations. Used PHPCodesniffer rules are Generic.Commenting,
Squiz.Commenting, PEAR.Commenting. Of course I applied only reasonable
sniffs from this standards.

@category tag has been deleted as deprecated accordingly to
phpDocumentor offical docs.

Ref: http://docs.phpdoc.org/references/phpdoc/tags/category.html

* [Slim] Refresh samples

samples/server/petstore/php-slim/lib/Model/ArrayOfArrayOfNumberOnly.php

@@ -1,11 +1,26 @@
 <?php
 /**
  * ArrayOfArrayOfNumberOnly
+ *
+ * PHP version 7
+ *
+ * @package OpenAPIServer\Model
+ * @author  OpenAPI Generator team
+ * @link    https://github.com/openapitools/openapi-generator
+ */
+
+/**
+ * NOTE: This class is auto generated by the openapi generator program.
+ * https://github.com/openapitools/openapi-generator
  */
 namespace OpenAPIServer\Model;
 
 /**
  * ArrayOfArrayOfNumberOnly
+ *
+ * @package OpenAPIServer\Model
+ * @author  OpenAPI Generator team
+ * @link    https://github.com/openapitools/openapi-generator
  */
 class ArrayOfArrayOfNumberOnly
 {