migrate workspace for @angular/core@9.0.0-beta

NGCC postinstall migration. Adds an ngcc invocation to npm/yarn's postinstall script. Read more about this here: https://v9.angular.io/guide/migration-ngcc

frontend/package.json

@@ -11,7 +11,7 @@
     "codecov": "codecov",
     "lint": "ng lint > tslint-result.txt",
     "e2e": "ng e2e",
-    "postinstall": "echo 'Replacing moment.js by empty file since it is optional and not used'; echo '' > node_modules/moment/moment.js"
+    "postinstall": "ngcc --properties es2015 browser module main --first-only --create-ivy-entry-points && echo 'Replacing moment.js by empty file since it is optional and not used'; echo '' > node_modules/moment/moment.js"
   },
   "private": true,
   "dependencies": {