[Doc request] Etcd and etcdctl

[theS1LV3R]

Feature request

Summary

Would be very nice to have the docs for etcd and etcdctl, as afaik they are commonly used within for example k8s

Examples

v2.3: https://etcd.io/docs/v2.3 (not the current version, but still very commonly used v3.5: https://etcd.io/docs/v3.5