Saying "Currently available locally" sounds more like an indicator than
"Availably locally" does. Centralizing translations avoids consistency
issues between shell context menus and sync folder context menu.
* SocketAPI has COPL_LOCAL_LINK / EMAIL_LOCAL_LINK commands
* The nautilus and dolphing shell integrations show a submenu from which
one can share as well as access the private link.
* The SocketAPI provides a new GET_STRINGS command to access localized
strings.
* The private link can also be accessed from the user/group sharing
dialog.
* The numeric file id is extracted from the full id to create the
private link url.
