feat(@angular/cli): add npm build script (#4949)

Author: filipesilva

packages/@angular/cli/blueprints/ng/files/package.json

@@ -5,6 +5,7 @@
   "scripts": {
     "ng": "ng",
     "start": "ng serve",
+    "build": "ng build",
     "test": "ng test",
     "lint": "ng lint",
     "e2e": "ng e2e"