@abstract
Submits the translation request and sends it to the translation provider.
During the translation process, Job::getItems() will only return job items that are not already fully translated.
\Drupal\tmgmt\JobInterface $job: The job that should be submitted.
hook_tmgmt_job_before_request_translation()
hook_tmgmt_job_after_request_translation()
public function requestTranslation(JobInterface $job);