auto-fill abstracts etc. with arxiv API

[cranmer]

from an email with Javier Montul working on INSPIRE next

It is a a mixture between this part of Invenio https://github.com/inveniosoftware/invenio/blob/master/invenio/ext/arxiv/__init__.py that allows to query arXiv and get Json back and then all the user facing part happens on JavaScript here:

• https://github.com/inspirehep/inspire-next/blob/master/inspire/modules/deposit/static/js/deposit/literature_submission_form.js#L562
• https://github.com/inspirehep/inspire-next/blob/master/inspire/modules/deposit/static/js/deposit/data_sources/arxiv.js

There is quite a lot of code ;) you can ask me some questions if you want.

[cranmer]

Noting that this is still not quite working