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/chezmoi.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:        "chezmoi",
 		Description: "Attribute modifier",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "manage", Description: "Add an existing file, directory, or symlink to the source state"},
 			{Name: "apply", Description: "Update the destination directory to match the target state"},
 			{Name: "archive", Description: "Generate a tar archive of the target state"},
@@ -53,7 +53,7 @@ func init() {
 			{Name: "help", Description: "Help about any command"},
 			{Name: "generate", Description: "Generate a file for use with chezmoi"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "--autotemplate", Description: "Generate the template when adding files as templates"},
 			{Name: "--create", Description: "Add files that should exist, irrespective of their contents"},
 			{Name: "--encrypt", Description: "Encrypt files"},