[DX] Re-work generate:bundle for simple app bundles #290

@weaverryan please review my pull request ;)
I'm not sure about writing these lines. The big reason is that if the user chooses shared=no here, then I think on the next step (namespace) we should re-word things to recommend that they don't have a vendor namespace there. And if they select shared=yes, then we would give them a recommendation that included a vendor namespace.