Update wizard restart text to take into account new package download process

If no package is embedded in the platform and packages are downloaded after the server restart, we need to update the text displayed at the Download and Restart steps.

Download step (http://localhost:8080/nuxeo/PackagesDownload ):

• EN: This is the list of the packages that will be downloaded.
• FR: Voici la liste des packages qui seront téléchargés.

Restart step (http://localhost:8080/nuxeo/Restart ):

• EN: The following add-ons you selected are being downloaded: <list of packages yet to download (by nuxeoctl)>
• FR: Les addons suivants sont en cours de téléchargement : <list des paquets restant à télécharger (par nuxeoctl)>