Tackling all missing language parameters in the fr.json5 file.

[pilasou]

Describe the bug

Since DSpace 9, all missing parameters in the fr.json5 file are flagged as TODO. 555 labels are missing. This tagging simplifies greatly translation works and all missing labels must now find its translation. :)

[pilasou]

Just to mention that me (@pilasou) and @nimabehforouz have extracted all missing translations (TODO) for the fr.json5 and have started to work on those translations.