Implement logic for searching for authors with first name and surname in NER project

[lizgzil]

https://github.com/wellcometrust/datalabs/pull/663

After the user research it was clear that people wanted to be able to search for someones full name.

So need to think about the search logic for this and what the return options would be.

e.g. if they search for John Smith, we want to give them the mentions of

• john smith
• j smith
• smith, j
• smith, john
• all smiths where no first name is mentioned? e.g. Smith et al...