workflows: holdingpen updates

* Adds link to arXiv for arXiv identifiers.

* Shows only INSPIRE categories.

* Change the type of process_record_arxiv workflow
  from 'record' to 'Harvested record' to be distinguished
  from submitted records.

* Adds the type 'Submitted record' to literature and
  literature_simple workflows.

* Adds task halt_to_render to literature_simple workflow
  in order to update the title and description columns in holdingpen
  maintable.

the title and description have been cached to redis in order to be refreshed the workflow has to be refreshed. halt_to_render halts the workflow so its status change and it get immediately awaken by the receiver in the overlay.