refactor(commands): separate commands and its core into two folders (#32)

- I think it would be better if one for commands only, one for the spec
handling core logic so people won't be confused by the core logic inside
the commands folder (cleaner I guess)
- Regen docs

commands/ops/cdk.go

@@ -1,14 +1,14 @@
 package ops
 
 import (
-	"github.com/versenilvis/iris/commands/core"
+	"github.com/versenilvis/iris/spec"
 )
 
 func init() {
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "cdk",
 		Description: "AWS CDK CLI",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "init", Description: "Create a new, empty CDK project from a template"},
 			{Name: "metadata", Description: "Returns all metadata associated with this stack"},
 			{Name: "doctor", Description: "Check your set-up for potential problems"},
@@ -25,7 +25,7 @@ func init() {
 			{Name: "context", Description: "Manage cached context values"},
 			{Name: "doc", Description: "Opens the reference documentation in a browser"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "--version", Description: "The current version"},
 			{Name: "-h", Description: "Show help"},
 		},