improve using IATI-Codelists-NonEmbedded location

* location was sometimes hardcoded
* use submodule https://github.com/IATI/IATI-Codelists-NonEmbedded at
${PATH_TO_SSOT}/IATI-Codelists-NonEmbedded (need to git add submodule)
* database name of dim_country was changed to codelist_country