Add the missing French (fr) translations across the calendar, node, orchestra, placement and order submodules

Adds French for ~95 previously untranslated strings across the calendar, node, orchestra, placement, order and ticket submodules (plus a few base strings), consistent with existing terminology (Créneau, Lieu, Flux de travail, Panier, Place, Tenant). Plural strings are added as msgid_plural entries. Also removes two pre-existing exact-duplicate entries so the file passes msgfmt -c. The yoyaku_manager scope strings are covered by their own issue.