Add JiHu QA environment

What does this MR do and why?

This is JiHu team, we want to setup a JH QA environment.

So we need load the JiHu environment in qa/qa/specs/spec_helper.rb like spec/spec_helper.rb did:

# spec/spec_helper.rb
require_relative('../jh/spec/spec_helper') if Gitlab.jh?

The whole MR can be found in Jihulab, and most of this is done internally by JiHu.

How to set up and validate locally

1. When not in JiHu environemnt, nothing will change here.
2. When in JiHu environment, it will load spec_helper of JiHu.

/cc @daveliu