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/kind.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:        "kind",
 		Description: "Cluster",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "Build", Description: "Build one of [node-image]"},
 			{Name: "node-image", Description: "Builds a node image"},
 			{Name: "architecture", Description: "Architecture to build for, defaults to the host architecture"},
@@ -34,7 +34,7 @@ func init() {
 			{Name: "image-archive", Description: "Loads docker images from archive into all or specified nodes by name"},
 			{Name: "version", Description: "Prints the kind CLI version"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "--arch", Description: "Architecture to build for, defaults to the host architecture"},
 			{Name: "--base-image", Description: "Base image to use for the node image"},
 			{Name: "--image", Description: "Name:tag of the resulting image to be built"},