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/wing.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:        "wing",
 		Description: "Runs a Wing executable in the Wing Console",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "run", Description: "Runs a Wing executable in the Wing Console"},
 			{Name: "executable", Description: "Executable .wx file"},
 			{Name: "compile", Description: "Compiles a Wing program"},
@@ -16,7 +16,7 @@ func init() {
 			{Name: "upgrade", Description: "Upgrades the Wing toolchain to the latest version"},
 			{Name: "help", Description: "Display help for command"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-h", Description: "Display help for command"},
 			{Name: "-o", Description: "Output directory"},
 			{Name: "-t", Description: "Target platform (options: 'tf-aws', 'sim')"},