README: archive project (coreos#2169)

This hasn't seen any activity in a while and there are no plans to
continue development.

README.md

@@ -1,18 +1,8 @@
 # etcd operator
-unit/integration:
-[![Build Status](https://jenkins-etcd-public.prod.coreos.systems/job/etcd-operator-unit-master/badge/icon)](https://jenkins-etcd-public.prod.coreos.systems/job/etcd-operator-unit-master/lastBuild/)
-e2e (Kubernetes stable):
-[![Build Status](https://jenkins-etcd-public.prod.coreos.systems/buildStatus/icon?job=etcd-operator-master)](https://jenkins-etcd-public.prod.coreos.systems/job/etcd-operator-master/)
-e2e (upgrade):
-[![Build Status](https://jenkins-etcd.prod.coreos.systems/buildStatus/icon?job=etcd-operator-upgrade)](https://jenkins-etcd.prod.coreos.systems/job/etcd-operator-upgrade/)
 
-### Project status: beta
+### Project status: archived
 
-Major planned features have been completed, and while no breaking API changes are currently planned, we reserve the right to address bugs and API changes in a backwards incompatible way before the project is declared stable. See [upgrade guide](./doc/user/upgrade/upgrade_guide.md) for a safe upgrade process.
-
-Currently user facing etcd cluster objects are created as [Kubernetes Custom Resources](https://kubernetes.io/docs/tasks/access-kubernetes-api/extend-api-custom-resource-definitions/), however, taking advantage of [User Aggregated API Servers](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/api-machinery/aggregated-api-servers.md) to improve reliability, validation and versioning is planned. The use of Aggregated API should be minimally disruptive to existing users but may change what Kubernetes objects are created or how users deploy the etcd operator.
-
-We expect to consider the etcd operator stable soon; backwards incompatible changes will not be made once the project reaches stability.
+This project is no longer actively developed or maintained. The project exists here for historical reference. If you are interested in the future of the project and taking over stewardship, please contact etcd-dev@googlegroups.com.
 
 ### Overview