Add how to cite for datasets

[cedrichotopp]

Added a module to build an APA citation for a dataset which is used when a citation cannot be fetched.
Added a button to the tile grid that opens a modal containing the citation data which can be easily copied.

[adkinsrs]

Everything looks good so far. Still need to run the actual testing of the codebase. I did make a couple minor comments though.

[adkinsrs]

Couple of notes:

1. I noticed the citation display box still allows for the user to select between 4 options. While it does work, along with the copy, we discussed last week just limiting it to APA citation format only just to keep things simple.

2. I tested two datasets I uploaded myself that did not have a Pubmed ID asssociated. For both of those, I got the following JS stacktrace

citation.js:34 Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'split')
    at citation.js:34:40
    at Array.map (<anonymous>)
    at Citation.APA (citation.js:32:27)
    at HTMLAnchorElement.<anonymous> (tilegrid.js:903:48)

It seems this should have been routed through the gEAR route instead of the APA route. For both of these entries I do have my own name as the "contact author" so that should have at least been populated in the "authors" parameter. Since I provide you with limited datasets, all of which probably have Pubmed IDs associated, I recommended temporarily rewiring the code to treat them as if the Pubmed ID was missing for now, so you can properly test that route.