add script to download k8s tooling with back-off mechanism

make fetch timeout configurable

add CNG image building pipeline

.gitlab/ci/cng-images.yml

@@ -0,0 +1,18 @@
+# Used by GitLab: https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab-ci.yml
+.gitlab-cng-matrix:
+  # image: registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.patched-golang-1.14-git-2.31-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-11-graphicsmagick-1.3.36
+  variables:
+    LFS: '2.9'
+    CHROME: '89'
+    NODE: '14.15'
+    YARN: '1.22'
+    GRAPHICSMAGICK: '1.3.36'
+    POSTGRESQL: '11'
+    RUBY: '2.7.patched'
+    GIT: '2.31'
+    GOLANG: '1.14'
+
+gitlab-cng push:
+  extends:
+    - .gitlab-cng-matrix
+    - .build_and_deploy_custom