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/sys/meroxa.go

@@ -1,14 +1,14 @@
 package sys
 
 import (
-	"github.com/versenilvis/iris/commands/core"
+	"github.com/versenilvis/iris/spec"
 )
 
 func init() {
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "meroxa",
 		Description: "The Meroxa CLI",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "accounts", Description: "Manage Meroxa Accounts"},
 			{Name: "ls", Description: "List Meroxa Accounts"},
 			{Name: "set", Description: "Set active account"},
@@ -42,7 +42,7 @@ func init() {
 			{Name: "version", Description: "Display the Meroxa CLI version"},
 			{Name: "help", Description: "Help about any command"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "--no-headers", Description: "Display output without headers"},
 			{Name: "--docker-hub-access-token", Description: "DockerHub access token to use to build and deploy the app"},
 			{Name: "--docker-hub-username", Description: "DockerHub username to use to build and deploy the app"},