Before:

$moderators = \Drupal::entityQuery('user')
 ->condition('status', 1)
 ->condition('roles', $moderator_role)
 ->execute();

After:

Add to settings.local.php:

use Drupal\Core\Mail\MailManagerInterface;

...

use Drupal\Core\Config\ConfigFactoryInterface;

...

 $config_factory = \Drupal::configFactory();
 $config = $config_factory->getEditable('system.maintenance');
 $config->set('message', 'test');
 $config->save(TRUE);

Create mymodule.links.task.yml and add some lines

   $content_entity_types = [];
   $entity_type_definations = \Drupal::entityTypeManager()->getDefinitions();
   /* @var $definition EntityTypeInterface */
   foreach ($entity_type_definations as $definition) {
     if ($definition instanceof ContentEntityType) {
       $content_entity_types[] = $definition;
     }
   }

$form['advanced'] = array(
 '#type' => 'details',
 '#title' => t('Advanced settings'),
 '#description' => t('Lorem ipsum.'),
 '#open' => TRUE, // Controls the HTML5 'open' attribute.

 $role_object = Role::load('authenticated');
 if ($role_object) {
   $role_object->grantPermission('mymodule write messages');
   $role_object->save();
 }

use Drupal\field\Entity\FieldStorageConfig;
use Drupal\field\Entity\FieldConfig;

/**
* Implements hook_uninstall().
*/
function