Codeception test adjustments for basic and advanced applications

- Moved everything test-related into `tests` directory. Codeception tests are in `codeception`.
- Removed database module since we're using fixtures and migrations.
- Moved console entry points and bootstrap into `tests/codeception/bin`.
- Adjusted travis build scripts.
- Adjusted documentation to be consistent and reflect changes made.

apps/basic/tests/codeception/bin/_console_bootstrap.php

@@ -0,0 +1,14 @@
+<?php
+
+defined('YII_DEBUG') or define('YII_DEBUG', true);
+
+defined('YII_ENV') or define('YII_ENV', 'test');
+
+// fcgi doesn't have STDIN and STDOUT defined by default
+defined('STDIN') or define('STDIN', fopen('php://stdin', 'r'));
+defined('STDOUT') or define('STDOUT', fopen('php://stdout', 'w'));
+
+defined('ROOT_DIR') or define('ROOT_DIR', dirname(dirname(dirname(__DIR__))));
+
+require(ROOT_DIR . '/vendor/autoload.php');
+require(ROOT_DIR . '/vendor/yiisoft/yii2/Yii.php');