Update URLs for GitLab JH

The development of GitLab JH is moved from https://gitlab.com/gitlab-jh/gitlab to https://jihulab.com/gitlab-cn/gitlab

We should update accordingly.

• Source link should use https://jihulab.com/gitlab-cn/gitlab
• Historical issues and merge requests links should stay as to keep the original context
• CI configurations should use our mirror for now https://gitlab.com/gitlab-org/gitlab-jh/gitlab (we can revisit to change to https://jihulab.com/gitlab-cn/gitlab after it's proven stable)

More context: https://gitlab.com/gitlab-jh/gitlab-jh-enablement/-/issues/156