[jjo] improve dind run-test-distros.sh via spec files

contrib/dind/kubespray-dind.yaml

contrib/dind/run-test-distros.sh

contrib/dind/test-most_distros-some_CNIs.env

contrib/dind/test-some_distros-kube_router_combo.env

contrib/dind/test-some_distros-most_CNIs.env