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/gh.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:        "gh",
 		Description: "Current branch",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "alias", Description: "Create command shortcuts"},
 			{Name: "delete", Description: "Delete an alias"},
 			{Name: "list", Description: "List available aliases"},
@@ -60,7 +60,7 @@ func init() {
 			{Name: "key-file", Description: "Path to the public key file"},
 			{Name: "key-id", Description: "ID of the key to delete"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-c", Description: "Name of the codespace"},
 			{Name: "--clone", Description: "Clone the fork {true|false}"},
 			{Name: "-y", Description: "Skip the confirmation prompt"},