MAINTAINERS: Merge the Gitlab-CI section into the generic CI section

MAINTAINERS: Merge the Gitlab-CI section into the generic CI section

The status of the gitlab-CI files is currently somewhat confusing, and
it is often not quite clear whether a patch should go via my tree or
via the testing tree of Alex. That situation has grown historically...
Initially, I was the only one using the gitlab-CI, just for my private
repository there. But in the course of time, the gitlab-CI switched to
use the containers from tests/docker/ (which is not part of the gitlab-CI
section in the MAINTAINERS file), and QEMU now even switched to gitlab.com
completely for the repository and will soon use it as its gating CI, too,
so it makes way more sense if the gitlab-ci.yml files belong to the people
who are owning the qemu-project on gitlab.com and take care of the gitlab
CI there. Thus let's merge the gitlab-ci section into the common "test and
build automation" section.

And while we're at it, I'm also removing the line with Fam there for now,
since he was hardly active during the last years in this area anymore.
If he ever gets more time for this part again in the future, we surely
can add the line back again. I'm also removing the Patchew URL from this
section now since Patchew's files are not tracked in the main QEMU repo
and it is also not maintained by Alex, Philippe and myself.
The maintainers of Patchew are still listed more accurately in the wiki on
https://wiki.qemu.org/AdminContacts & https://wiki.qemu.org/Testing/CI/Patchew
instead.

Now to avoid that Alex is listed here in this section alone, Philippe and
I agreed to help as backup maintainers here, too. And Willian volunteered
to be an additional reviewer.

Message-Id: <20210309112356.737266-1-thuth@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Acked-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Acked-by: Fam Zheng <fam@euphon.net>
Signed-off-by: Thomas Huth <thuth@redhat.com>