Added french translation files for backend and frontend.

backend/en/basis.json

@@ -59,7 +59,7 @@
         "oak": "Objects on map",
         "record_history": "Record history",
         "loans": "Loan Management",
-        "exhibitions": "Exhibits",
+        "exhibitions": "Exhibitions",
         "restoration": "Restoration",
         "provenanceresearch": "Provenance research",
         "account_settings": "Account settings",