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/kamal.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:        "kamal",
 		Description: "Skip image build and push",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "boot", Description: "Boot new accessory service on host (use NAME=all to boot all accessories)"},
 			{Name: "upload", Description: "Upload accessory files to host"},
 			{Name: "directories", Description: "Create accessory directories on host"},
@@ -21,7 +21,7 @@ func init() {
 			{Name: "status", Description: "Show status of accessory on host"},
 			{Name: "remove", Description: "Remove accessory container, image and data directory from host"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-P", Description: "Skip image build and push"},
 			{Name: "--since", Description: "Number of lines to show from each server"},
 			{Name: "--grep", Description: "Show lines with grep match only (use this to fetch specific requests by id)"},