* Add `dockerfile.stages.*.extra_directories` as an optional list of strings (used in the Drupal Commerce Kickstart example).
* Allow `php.phpstan` and `php.phpcs` to be `false` or a Collection so their configuration files can not be generated (used in the Drupal Commerce Kickstart example).
* Add `php.phpunit` and allow it to be set to `false` so its configuration files can not be generated (used in the Drupal Commerce Kickstart example).
* No further PHPUnit configuration is supported.
* Add `database.extra_databases`
* Add `php.phpstan.baseline` as an optional boolean.