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/k9s.go

@@ -1,19 +1,19 @@
 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:        "k9s",
 		Description: "Kubernetes namespace",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "help", Description: "Help about any command"},
 			{Name: "info", Description: "Print configuration info"},
 			{Name: "version", Description: "Print version/build info"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-h", Description: "Help for info"},
 			{Name: "-s", Description: "Prints K9s version info in short format"},
 			{Name: "-A", Description: "Launch K9s in all namespaces"},