Refactoring : use CSV for external data files

[ghusta]

See benefit of CSV files with GitHub :

• https://docs.github.com/en/repositories/working-with-files/using-files/working-with-non-code-files#rendering-csv-and-tsv-data

CSV files can be imported into PostgreSQL tables thanks to :

• COPY / CSV Format

[ghusta]

Also fixed some characters for UTF-8