Issue #2219009 by pwolanin: Improve DX of Settings class.

core/authorize.php

core/core.services.yml

core/includes/bootstrap.inc

core/includes/common.inc

core/includes/database.inc

core/includes/file.inc

core/includes/install.core.inc

core/includes/install.inc

core/includes/mail.inc

core/includes/session.inc

core/includes/theme.maintenance.inc

core/lib/Drupal/Component/Diff/DiffEngine.php

core/lib/Drupal/Component/PhpStorage/PhpStorageFactory.php

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

core/lib/Drupal/Core/Authentication/Provider/Cookie.php

.../lib/Drupal/Core/Config/BootstrapConfigStorageFactory.php

core/lib/Drupal/Core/CoreServiceProvider.php

core/lib/Drupal/Core/Extension/ExtensionDiscovery.php

core/lib/Drupal/Core/Form/FormBuilder.php

core/lib/Drupal/Core/Mail/Plugin/Mail/PhpMail.php