Add CITATION.bib file to make citing RMG easier

[JacksonBurns]

Motivation or Problem

RMG-py provides a list of citations, but does not take advantage of the GitHub Cite this Repository feature which automatically provides BibTex files with appropriate citations to users.

Description of Changes

This PR adds a single CITATION.cff file that is (hopefully) correctly formatted and accurate.

Testing

After merging, GitHub will automatically detect the file and add a Cite this Repository button, and any formatting/accuracy issues will then be obvious.

Reviewer Tips

The CITATION.cff file format is described here.

[yunsiechung]

I made a pull request (#2351) to add the RMG database paper (doi:10.1021/acs.jcim.2c00965) to the "How to cite" section in the README.md file. Will you add that to the CITATION.cff file?

[JacksonBurns]

Additional paper added. When pushed, it renders a button like this on the repository:

See it for yourself here.

[yunsiechung]

Looks good!
It looks like the branch is be behind the main branch. Could you rebase it with the latest main branch and push again?

[JacksonBurns]

Done!

[yunsiechung]

I think we usually rebase the branch with main and force-push the branch, so we don't have an additional commit like 1f182aa.

If you RMG's official git repo is called official, it will follow:
git fetch official
git rebase official/main
git push -f official [name_of_the_branch_to_push]

Will you undo your last commit (git reset HEAD~1) and follow the procedure above?
Also, the first two commits can be combined as one commit to minimize the number of commits.

[JacksonBurns]

Can you squash and merge instead? Seems cleaner than undoing a commit, combining two commits, and then rebasing.

[JacksonBurns]

Moved to #2357