Refactor LDAP docs
What does this MR do?
Refactor LDAP docs:
- Move EE relevant stuff in the EE doc
- Mention multiple LDAP servers (per Job's request)
- Cleanup code blocks with cleaner comments
- Add missing cron worker in
gitlab.yml.example
CE-MR: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/15814
Edited by 🤖 GitLab Bot 🤖