Generate certs for aggregation layer

Will be used for api server flags: --proxy-client-cert-file, --proxy-client-key-file
https://kubernetes.io/docs/tasks/access-kubernetes-api/configure-aggregation-layer/

Related story: https://mirantis.jira.com/browse/PROD-24599

Change-Id: I673665949fd912ace5332c2dfd6500a61d45b136
2 files changed