Add code field for paper BibTeX

[johannesjmeyer]

In the quantum bibstyle, a new non-standard code field is introduced that allows authors to add code to references, e.g. GitHub repositories. It would be good if that feature could also be supported in O-3PO and if it would be rendered in the BibTeX.

Seen that Crossref creates its own bibliography exports from the Metadata, maybe this should also be added there somehow, maybe through a note tag, but I don't know how CrossRef works so I can't elaborate on the ways this could be properly exported there.

[cgogolin]

Is there a paper on the arXiv that uses this feature that I could use for development and testing?

[johannesjmeyer]

No, sadly not because that was our invention as far as I recall