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/vercel.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:        "vercel",
 		Description: "CLI Interface for Vercel.com",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "deploy", Description: "Performs a deployment (default)"},
 			{Name: "dev", Description: "Start a local development server"},
 			{Name: "env", Description: "Manages the Environment Variables for your current Project"},
@@ -60,7 +60,7 @@ func init() {
 			{Name: "old name", Description: "Old name of the secret to rename"},
 			{Name: "new name", Description: "New name of the secret"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-h", Description: "Output usage information"},
 			{Name: "-v", Description: "Output the version number"},
 			{Name: "-V", Description: "Set the platform version to deploy to"},