Use ConfigurableLanguage configuration entity instead of language_save() and language_delete()

Drupal 8 uses the configuration entity system to provide user configurable languages.

This is a Drupal 8 to Drupal 8 change record

Before

Creating a language from the predefined list

  $language = new Language(array('id' => 'fr'));
  language_save($language);

Creating a custom language

  $language = new Language(array('name' => $this->randomMachineName(), 'id' => 'l2', 'locked' => TRUE));
  language_save($language);

Deleting a language

  language_delete('en');

After

Creating a language from the predefined list

  ConfigurableLanguage::createFromLangcode('fr')->save();

Creating a custom language

  ConfigurableLanguage::create(array('label' => $this->randomMachineName(), 'id' => 'l2', 'locked' => TRUE))->save();

Deleting a language

  ConfigurableLanguage::load('en')->delete();