Projects with missed layers

[mrsndmn]

ThreeDotsLabs/wild-workouts-go-ddd-example#47

Would it be a good idea to fail go-cleanarch or just warn to log if any layer was not found in project directory?

This behavior could be enabled with extra flag but IMO it would be better to turn this feature on by default.

Also its hard to determine if go-cleanarch found any layer in you module. I guess it would be nice feature if go-cleanarch plot project map like this (or even more pretty one)):

trainer Layers: application, domain, infrastructure, interfaces
trainings Layers:application, domain, infrastructure, interfaces