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.

Instead of `<p>` and `<b>` and `<br/>` it is better seen to use `<hX>` and `<li>` etc. for better styling options with bootstrap.

Can you amend these templates to take inspiration from https://github.com/inspirehep/invenio/commit/c9e4290fb6116243b42213aae05952a5e9715b1c#diff-38beb68ffdb5a5650df1cf347dd27521R44 ?