I decided to show gitlab as one big blob because it's effectively how
it works for users and us. Previously, git, gitolite and jenkins were
actually three different services, possibly split over multiple
machines.

In GitLab, only the runner is separate and that's mostly a distraction
that's part of GitLab's design, so we don't show them separately (just
like we didn't show Jenkins builders separately).

We attach one minio node per gitlab pages host. This might not be how
it works, but it seems simpler to show it that way: worst case, the
minio host gets decoupled and the gitlab pages webserver caches its
content anyways.

I hadn't realized that Jenkins was such a key component for static
websites, so it seems it belongs here as well.

Also add the public, to show where the actual files get fetched from.