Consider adding more context for citation formatting

One comment re: wording [for citation guidance] to perhaps consider: That we generally want to ask people to cite both software and paper (if there is a paper) is an institutional practice we chose. But prioritizing the paper citation can also be a choice, which can result in actually wanting the paper citation to show up on the sidebar on GitHub (and perhaps including the code citation BibTeX in the README instead).

I don't have a good suggestion for how to convey this being a choice when instantiating the template, and of course there are a variety of reasons why code as a first-class citizen in citation networks should be promoted. So maybe this is best deferred to considering at a later time.

Originally posted by @hlapp in https://github.com/Imageomics/Collaborative-distributed-science-guide/pull/69#pullrequestreview-4189999222

We may consider including more context in a collapsible box/admonition for those interested in deciding between the two options. The preferred option is still to have a code citation and ask for paper citation in the README.

Beginne damit, die Hinweise zu Zitationen und ihre Vorlage im Leitfaden zu finden, und lies dann die umgebende Formulierung sowie alle bestehenden Konventionen für Admonitions oder aufklappbare Boxen. Als erledigt gilt die Ergänzung eines Kontexts für die Wahl zwischen Code- und Paper-Zitationen, wobei die angegebene Präferenz für eine Code-Zitation erhalten bleibt und die Paper-Zitation im README angefordert wird.