initial implementation of media_entity Instagram plugin.

I need it. If I remove it, I get:
Recoverable fatal error: Argument 4 passed to Drupal\media_entity_instagram\Plugin\MediaEntity\Type\Instagram::__construct() must be an instance of GuzzleHttp\ClientInterface, instance of Drupal\Core\Entity\EntityManager given, called in /Users/malina/Sites/pubtool.dev/docroot/modules/contrib/media_entity_instagram/src/Plugin/MediaEntity/Type/Instagram.php on line 75 and defined in Drupal\media_entity_instagram\Plugin\MediaEntity\Type\Instagram->__construct() (line 88 of /Users/malina/Sites/pubtool.dev/docroot/modules/contrib/media_entity_instagram/src/Plugin/MediaEntity/Type/Instagram.php).