Split `.gitlab-ci.yml` into multiple includes
What does this MR do?
This tries to break the complexity of .gitlab-ci.yml
by splitting
it into multiple includes that provide functional parts for different test scenarios
and are "almost independent".
EE version: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/10854
Does this MR meet the acceptance criteria?
Conformity
Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/58521.
Edited by Rémy Coutable