docs(): guide for Angular Universal SSR

[codediodeio]

Checklist

• Issue number for this PR: docs(ssr): Documentation for server-side rendering with Angular Universal #1685
• Docs included?: Yes
• Test units included?: n/a
• In a clean directory, yarn install, yarn test run successfully? yes

Description

Step by step guide for Angular v6 Universal SSR

[hiepxanh]

npm install --save-dev express webpack-cli ts-loader ws xmlhttprequest should adding webpack

[somombo]

i think it will be more relevant if this guide shows how to leverage firebase cloud functions

[codediodeio]

@somombo I worked on SSR on Cloud Functions this weekend, but was not able to get it fully working in production. It's possible to deploy a function that works locally, but Universal will fail with the following error when it goes live. Not sure how to fix it yet...

Unhandled Promise rejection: el.querySelector is not a function ; Zone: <root> ;

[kanafghan]

Isn't it worth mentioning that ng run YOUR_PROJECT_NAME:server will actually use the dev configuration, i.e. environment.ts and not environment.prod.ts, while ng build --prod is actually building the client for production?