Add Citation file

[matsvanes]

Think this is well worth looking at for making osl citable: https://citation-file-format.github.io/#/create-a-citationcff-file-now citation-file-format.github.io Citation File Format (CFF) Landing page for the Citation File Format (CFF), a YAML 1.2-based format for providing citation metadata for (research/scientific) software. 7:43 Will integrate with github to provide an automatically generated copy-paste citation in a few formats https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-citation-files