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/networksetup.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:        "networksetup",
 		Description: "Configuration tool for network settings in macOS",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "computername", Description: "The new name for your computer on the network"},
 			{Name: "ip", Description: "The IP address to set for the network service"},
 			{Name: "subnet", Description: "The subnet mask to apply"},
@@ -49,7 +49,7 @@ func init() {
 			{Name: "pppoeName", Description: "Optional name for the PPPoE service"},
 			{Name: "location", Description: "The name for the new location"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-listnetworkserviceorder", Description: "Displays a list of all the network services on the server's hardware ports"},
 			{Name: "-listallhardwareports", Description: "Displays ethernet (or Wi-Fi) address for hardwareport or device specified"},
 			{Name: "-getcomputername", Description: "Displays the computer name"},