JOSS publication

[colinsauze]

Submit CATS to the Journal of Open Source Software

[andreww]

Brief update on this - I now have a very rough first draft (on google docs). I'll ask @sadielbartholomew and/or @Llannelongue to take a look before I migrate it to the repository (and to markdown) in a couple of weeks. In drafting, I've found a couple of issues / potential things we could improve. I'll open new issues for these. Oh, and we should also check the JOSS requirement checklist for anything else we need to do to the codebase.