Add workflow step for UK curation

[michamos]

We need to add a workflow step to create tickets for UK curation in the proper functional category/queue. Any new core arXiv paper that has fulltext matching the following regex should be assigned to the UK curation functional category:

\b(UK|United\s+Kingdom|England|Scotland|Northern\s+Ireland)\b

We can duplicate the logic of https://github.com/inspirehep/inspire-next/blob/fab1c19d33d7a5c6ba543aedcc9f9ddef814787a/inspirehep/modules/workflows/workflows/article.py#L264-L272, modifying the details to fit the UK regex and queue.

Note that unlike for HAL, we only want to create tickets for core records (core:true), so we need an additional check.

[michamos]

I've tested it and it seems to work well, so ready to deploy as far as I'm concerned 🚀