feat: add gitlab as optional bigbang addon

CHANGELOG

base/gitrepository.yaml

chart/templates/NOTES.txt

chart/templates/_helpers.tpl

chart/templates/argocd/namespace.yaml

chart/templates/clusterauditor/namespace.yaml

chart/templates/gatekeeper/namespace.yaml

chart/templates/gitlab/gitrepository.yaml

chart/templates/gitlab/helmrelease.yaml

chart/templates/gitlab/namespace.yaml

chart/templates/istio/controlplane/namespace.yaml

chart/templates/istio/operator/namespace.yaml

chart/templates/logging/eck-operator/namespace.yaml

chart/templates/logging/elasticsearch-kibana/namespace.yaml

chart/templates/monitoring/namespace.yaml

chart/templates/twistlock/namespace.yaml

chart/templates/values.yaml

chart/values.yaml

scripts/deploy/01_deploy_bigbang.sh

scripts/deploy/02_wait_for_helmrealeases.sh