Currently, I get warnings like this in all blueprints I help maintain

The option '--node-version' is not registered with the 'new' command. 
Run `ember new --help` for a list of supported options.

I believe the problem here is that the command for blueprints is what defines the flags, and not the actual blueprints themselves.

This is a factoring problem, because it means if a blueprint wants to eliminate the warning, they must add it to ember-cli (or just not use ember-cli for blueprint generation (or just deal with the unprofesh warning 🙈 ))

Do we have a path to pushing flags into blueprints? or allowing blueprints to specify what flags they want to support?