Add Citeproc functionality

[mbollmann]

This PR adds citeproc functionality into the new library.

[mbollmann]

@mjpost Codecov is not (fully?) working here, it only shows some of the recent commits and gives an error in the workflows here:

[2024-04-14T16:45:27.700Z] ['error'] There was an error running the uploader: Error uploading to [https://codecov.io:](https://codecov.io/) Error: There was an error fetching the storage URL during POST: 404 - {'detail': ErrorDetail(string='Unable to locate build via Github Actions API. Please upload with the Codecov repository upload token to resolve issue.', code='not_found')}

Can you check if it’s authorized properly?

[mjpost]

Hi @mbollmann, can you remind me how to do that?

[mbollmann]

@mjpost I made a request to authorize the Codecov app; can you see it? There also needs to be a token added to the repository secrets as described here.