Allow skipping generating route and/or controller with view_with_vue generator

[joekrump]

This could be handy in cases where a view already exists because it was already generated by something such as the scaffold generator.

If a person wants to just replace the index view with a view that uses Vue.js for part of its rendering, then they may not want to have a new route entry defined (since one already exists) or a new controller method (since that already exists too)