Refactor pipeline configuration

.gitlab-ci.yml

.gitlab/ci/Dockerfile

.gitlab/ci/scripts/gitlab_release.sh

.gitlab/ci/scripts/release_s3.sh

.gitlab/ci/yaml/_common.gitlab-ci.yml

.gitlab/ci/yaml/_rules.gitlab-ci.yml

.gitlab/ci/yaml/build.gitlab-ci.yml

.gitlab/ci/yaml/postrelease.gitlab-ci.yml

.gitlab/ci/yaml/prepare.gitlab-ci.yml

.gitlab/ci/yaml/release.gitlab-ci.yml

.gitlab/ci/yaml/validate.gitlab-ci.yml