Auto-strip scopes from app name

[digitalsadhu]

If a package.json file has a name field of @finn-no/my-app then this will break and the user will get a nice message saying that they need to fix it or set app name it in config.

Got a feedback comment about the possibility of stripping out scopes as well. Is this something we might want to consider or is the current mechanism of telling the user clearly what they need to do enough?