* Update Kubernetes to v1.21.0
* Update to golang v1.16.2
* Update dependent modules to track with upstream
* Switch to upstream flannel
* Track changes to upstream cloud-controller-manager and FeatureGates
Signed-off-by: Brad Davidson <brad.davidson@rancher.com>
* Add functionality for etcd snapshot/restore to and from S3 compatible backends.
* Update etcd restore functionality to extract and write certificates and configs from snapshot.