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/ansible_galaxy.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:        "ansible-galaxy",
 		Description: "The Galaxy API server URL",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "collection", Description: "Operate on collections"},
 			{Name: "download", Description: "Download collections"},
 			{Name: "init", Description: "Initialize collections"},
@@ -30,7 +30,7 @@ func init() {
 			{Name: "info", Description: "Role information"},
 			{Name: "install", Description: "Install roles"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "--server", Description: "The Galaxy API server URL"},
 			{Name: "--token", Description: "Ignore SSL certificate validation errors"},
 			{Name: "--clear-response-cache", Description: "Clear the existing server response cache"},