Is there a way to suppress warnings on the D8 Status Report page?
Unfortunately there is no hook_requirements_alter yet. As a workaround you may override system manager service which is responsible for invoking that hook.

src/SystemManager.php
    

namespace Drupal\example;

use Drupal\system\SystemManager as DefaultSystemManager;

/**
 * System Manager Service.
 */
class SystemManager extends DefaultSystemManager {

  /**
   * {@inheritdoc}
   */
  public function listRequirements() {
    // Suppress some unwanted warnings on Status report page.
    return array_filter(parent::listRequirements(), function ($requirement) {
      return $requirement['title'] != t('The message about CDN.');
    });
  }

}


src/ExampleServiceProvider.php
    

namespace Drupal\example;

use Drupal\Core\DependencyInjection\ContainerBuilder;
use Drupal\Core\DependencyInjection\ServiceProviderBase;

/**
 * Overrides the system manager service to suppress some warnings.
 */
class ExampleServiceProvider extends ServiceProviderBase {

  /**
   * {@inheritdoc}
   */
  public function alter(ContainerBuilder $container) {
    $container-&gt;getDefinition('system.manager')
      -&gt;setClass('Drupal\example\SystemManager');
  }

}