Add docs for citation best practices

[HaleySchuhl]

Can we add more detail to docs page about how to cite a specific version or tutorial, for presentations and publication. Very few references, if at all, on the documentation page even though there's this section in the readme of the project.

Citing PlantCV
If you use PlantCV, please cite the PlantCV publications relevant to your work. To see how others have used PlantCV in their research, check out our list of publications using PlantCV.

Additional context
https://docs.github.com/en/repositories/archiving-a-github-repository/referencing-and-citing-content