Add support for PubMed RIS format

Description

Closes issues: LA-1529 Related issues:

The new PubMed has no direct link to XML link from the article page, they do however have a download link to .ris-format. Added support for this format, alongside XML format.

Notes to reviewer

Tested parser against 113 000 references without error. There are quite a few differences from the XML parsing, but as far as I can tell, this is mainly punctuation and abbreviated vs written out author first name.

Type of change

Application (affects UI or general functionality):

• New feature
• Bug fix
• Improvement

Ops / admin / CI related only (not impacting users):

• New feature
• Bug fix
• Improvement

Tests

General

• Tests have been added that prove my fix is effective or that my feature works
• Related tests have been modified/removed

Hypothesis testing:

• Soak testing has been done
• Distribution between positive / negative cases has been checked

Database

• Includes changes to database schema
• Includes necessary database migrations

Configuration

• Includes changes to configuration
• Includes configuration migration instructions in documentation

Merge checklist

• Self-review of code performed
• Feature review against specification (if applicable)
• Need for documentation has been evaluated and, if necessary, updated
• Code and implementation is reviewed by other core developer (all changes, inc. changes based on initial review)