Adding Corsican localization to MozBackup

[Patriccollu]

Hello,

Even if MozBackup project does not look to be very active any more... ;-)

I would like to contribute with a brand new localization in Corsican!

The language file has been based on versions 1.5.1 and 1.5.2-beta1 which doesn't contain any new/modified string.

It is delivered as the other languages: corsican.zip file containing a single Default.lng language file.

Best regards, Patriccollu di Santa Maria è Sichè.