Add Croatian to the language options

[grantfitzsimmons]

https://hosted.weblate.org/projects/specify-7/-/hr/

[melton-jason]

For those that are implementing this, be sure to review the Adding a New Language section of the Frontend Localization documentation: https://github.com/specify/specify7/tree/main/specifyweb/frontend/js_src/lib/localization#adding-new-language!