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/js/playwright.go

@@ -1,20 +1,20 @@
 package js
 
 import (
-	"github.com/versenilvis/iris/commands/core"
+	"github.com/versenilvis/iris/spec"
 )
 
 func init() {
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "playwright",
 		Description: "Display help for command",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "test", Description: "Run tests with Playwright Test"},
 			{Name: "tests", Description: "Test files to run"},
 			{Name: "install", Description: "Running without arguments will install default browsers"},
 			{Name: "browsers", Description: "Browser to install"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "--help", Description: "Display help for command"},
 			{Name: "-g", Description: "Run the test with the title"},
 			{Name: "--headed", Description: "Run tests in headed browsers"},