Improve database: add first author name et al to Reference column

[jamesmbaazam]

• Please check if the PR fulfills these requirements

• I have read the CONTRIBUTING guidelines
• A new item has been added to NEWS.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• Checks have been run locally and pass

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

Docs update.

• What is the current behavior? (You can also link to an open issue here)

The parameter database has a "Reference" column that only lists the DOI, making it hard to know who published the paper.

• What is the new behavior (if this is a feature change)?

Improves the "reference" column by adding the first author's family name et al and year.

• Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?)

No.

• Other information:

This PR fixes #347.

[joshwlambert]

When I rendered the database vignette with the new changes made in this PR some of the entries did not render as expected. These include: single author entries that do not require "et al.", double author entries that should state both author names, and entries where the first author is an organisation or team (e.g. WHO Ebola response team) where they do not have a family name ($family).

I'll fix these on this PR and then merge.

[joshwlambert]

Thank you for proposing and making this change @jamesmbaazam, it's definitely an improvement to the usability of the database.