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/vela.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:        "vela",
 		Description: "Show the reference doc for component, trait or workflow types",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "show", Description: "Show the reference doc for component, trait or workflow types"},
 			{Name: "env", Description: "Manage environments for vela applications to run"},
 			{Name: "delete", Description: "Delete an environment"},
@@ -56,7 +56,7 @@ func init() {
 			{Name: "export", Description: "Export deploy manifests from appfile or application"},
 			{Name: "version", Description: "Prints the version"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-e", Description: "Specify environment name for application"},
 			{Name: "--help", Description: "Help for show command"},
 			{Name: "-n", Description: "Specify the Kubernetes namespace to use"},