Add needs for all jobs which require setup-test-env and
move review-build-cng to additional stage review-prepare
to decrease wait time for jobs in pipeline

These files are not available in CE, resulting in CI pipeline failures
when trying to include these files. Since the job is already configured
to only run on EE, we can just include it in both CE and EE.

Having these defined in both CE and EE won't hurt anything.

Signed-off-by: Rémy Coutable <remy@rymai.me>

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

Part of: https://gitlab.com/gitlab-org/gitaly/issues/1715

MySQL support has been removed

Two static memory benchmarks will be included in our CI pipeline. It
will load gems from the Gemfile and check the amount of RAM consumed
as well as the number of objects allocated and retained.
Aggregated values will be included as 'metrics' into MRs while full
reports will be downloadable as job artifacts.

This commit adds CI job that validates all `*.yml`
with `yamllint`.

This commit fixes all offenses present in repository.

This reverts commit 744f1f2e, reversing
changes made to c4d930e5.

This reverts merge request !27514

Signed-off-by: Rémy Coutable <remy@rymai.me>

Ruby 2.6 offers better performance and memory usage:
https://www.rubyguides.com/2018/11/ruby-2-6-new-features/

Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/57323