feat(input): Full refacto of the user input system

templates/go-swagger/api.yaml.tmpl

@@ -7,7 +7,9 @@ info:
   contact:
     name: "{{ .ProjectContact.Name }}"
     email: "{{ .ProjectContact.Email }}"
+{{if .ProjectContact.URL }}
     url: "{{ .ProjectContact.URL }}"
+{{end}}
 consumes:
   - "application/json"
 produces: