Issue #2225265 by eojthebrave: Add Utility group/topic for api.drupal.org

core/lib/Drupal/Component/Utility/Crypt.php

core/lib/Drupal/Component/Utility/DiffArray.php

core/lib/Drupal/Component/Utility/Html.php

core/lib/Drupal/Component/Utility/Image.php

core/lib/Drupal/Component/Utility/Json.php

core/lib/Drupal/Component/Utility/NestedArray.php

core/lib/Drupal/Component/Utility/Number.php

core/lib/Drupal/Component/Utility/Random.php

core/lib/Drupal/Component/Utility/Settings.php

core/lib/Drupal/Component/Utility/SortArray.php

core/lib/Drupal/Component/Utility/String.php

core/lib/Drupal/Component/Utility/Tags.php

core/lib/Drupal/Component/Utility/Timer.php

core/lib/Drupal/Component/Utility/Unicode.php

core/lib/Drupal/Component/Utility/UrlHelper.php

core/lib/Drupal/Component/Utility/UserAgent.php

core/lib/Drupal/Component/Utility/Variable.php

core/lib/Drupal/Component/Utility/Xss.php

core/modules/system/core.api.php