Refactor admin frontend build

cmd/gateway/admin_static.go

@@ -1,20 +1,15 @@
 package main
 
 import (
-	"embed"
 	"net/http"
 
 	"github.com/tursom/mc-gateway/internal/adminhttp"
 )
 
-//go:embed admin_static/index.html admin_static/app.css admin_static/app.js
-var adminStaticFS embed.FS
-
 func newGatewayHTTPHandler() http.Handler {
 	return adminhttp.NewGatewayHandler(adminhttp.GatewayHandlerOptions{
 		AdminPath:        adminStartup.AdminPath,
 		AdminAPIPrefix:   adminStartup.AdminAPIPrefix,
-		Assets:           adminStaticFS,
 		APIHandler:       newAdminAPIHandler(),
 		WebSocketEnabled: config.WebSocket.Enable,
 		WebSocketPath:    normalizedWebSocketPath(),