Display "Recent papers citing this work" panel on published projects

[tompollard]

All projects are now assigned DOIs, meaning that we should be able to retrieve papers that formally cite them (e.g. via the pubmed, pubmed central, or google scholar APIs).

It would be great if we could (1) retrieve lists of recent publications citing our projects and (2) display the list alongside project content.

e.g. I go to: https://physionet.org/content/mimiciii/1.4/. On this page I see a list of 5 recent publications that have cited the dataset using one of its DOIs.

Note that a single project has multiple DOIs - one core DOI that resolves to the latest version, and one DOI for each version.