Removed wg-cluster-api directory

Cluster API was removed as a working group and added as a
sub-project of sig-cluster-lifecycle in
https://github.com/kubernetes/community/pull/2592.

wg-cluster-api/OWNERS

@@ -1,6 +0,0 @@
-reviewers:
-  - wg-cluster-api-leads
-approvers:
-  - wg-cluster-api-leads
-labels:
-  - wg/cluster-api

wg-cluster-api/README.md

@@ -1,28 +0,0 @@
-<!---
-This is an autogenerated file!
-
-Please do not edit this file directly, but instead make changes to the
-sigs.yaml file in the project root.
-
-To understand how this file is generated, see https://git.k8s.io/community/generator/README.md
---->
-# Cluster API Working Group
-
-Define a portable API that represents a Kubernetes cluster. The API will contain the control plane and its configuration and the underlying infrastructure (nodes, node pools, etc).
-
-## Meetings
-* Regular WG Meeting: [s at  ]() (). [Convert to your timezone](http://www.thetimezoneconverter.com/?t=&tz=).
-  * [Meeting notes and Agenda](https://docs.google.com/document/d/16ils69KImmE94RlmzjWDrkmFZysgB2J4lGnYMRN89WM/edit).
-
-## Organizers
-
-* Kris Nova (**[@kris-nova](https://github.com/kris-nova)**), Heptio
-* Robert Bailey (**[@roberthbailey](https://github.com/roberthbailey)**), Google
-
-## Contact
-* [Slack](https://kubernetes.slack.com/messages/cluster-api)
-* [Mailing list](https://groups.google.com/forum/#!forum/kubernetes-sig-cluster-lifecycle)
-
-<!-- BEGIN CUSTOM CONTENT -->
-
-<!-- END CUSTOM CONTENT -->