Auto log

Part of Auto DevOps https://gitlab.com/gitlab-org/gitlab-ce/issues/35712

Auto log automatically gatherers and searches the logs of applications that are deployed with GitLab.

Considerations:

1. Use the Elastic Search cluster already needed for GitLab Search? Does logging need different tuning than search? Is it a problem that CE doesn't do search via Elastic Search?
2. Should we use FluentD since it is a cloud native standard?
3. How do we allow people to search the logs from GitLab?
4. How much should we help with tuning and maintaining the Elastic Search installation?
5. Should we only gather application logs or many more?

/cc @markpundsack