Review French translations in the Admin Center

Review translations from NXP-14213:
> b7ea2d2 NXP-14213 fix typos
> 735b001 Merge pull request #16 from cyop/master
> 3f2d284 FIX bug 14213 - Traducction FR

There are still typos and wrong translations. For instance:

label.displayDependencies.titles.needdownload=New packages that need to be downloaded and installed:
label.displayDependencies.titles.needdownload=Paquet(s) déjà téléchargé(s) à télécharger et installer:

=> Compare https://github.com/nuxeo/nuxeo/blob/master/nuxeo-features/nuxeo-admin-center/nuxeo-admin-center/src/main/resources/i18n/messages_fr.properties with https://github.com/nuxeo/nuxeo/blob/master/nuxeo-features/nuxeo-admin-center/nuxeo-admin-center/src/main/resources/i18n/messages_en.properties