Issue #3284370 by kumikoono, yas, shota niioka: Add a BDD test directory for OpenStack module

modules/cloud_service_providers/openstack/tests/src/Behat/behat.yml

+imports:
+  - ../../../../../../../cloud/tests/src/Behat/behat.yml
+default:
+  suites:
+    default:
+      contexts:
+        - Drupal\Tests\openstack\Behat\features\bootstrap\FeatureContext
+        - Drupal\Tests\cloud\Behat\features\bootstrap\FeatureContext
+        - Drupal\DrupalExtension\Context\DrupalContext
+        - Drupal\DrupalExtension\Context\MinkContext
+        - Drupal\DrupalExtension\Context\MessageContext
+        - Drupal\DrupalExtension\Context\DrushContext
+        - Drupal\DrupalExtension\Context\MarkupContext
+        - Drupal\DrupalExtension\Context\RandomContext
+        - Drupal\DrupalExtension\Context\BatchContext

modules/cloud_service_providers/openstack/tests/src/Behat/features/bootstrap/FeatureContext.php

+<?php
+
+namespace Drupal\Tests\openstack\Behat\features\bootstrap;
+
+use Drupal\DrupalExtension\Context\RawDrupalContext;
+
+/**
+ * Defines application features from the specific context.
+ */
+class FeatureContext extends RawDrupalContext {
+
+  /**
+   * Initializes context.
+   *
+   * Every scenario gets its own context instance.
+   * You can also pass arbitrary arguments to the
+   * context constructor through behat.yml.
+   */
+  public function __construct() {
+  }
+
+}