Transition from WG AI Conformance to a Subproject in SIG Architecture

The WG goals of establishing a new conformance program specific to AI platforms on top of Kubernetes have been met.
We are proposing winding down the WG and moving it into SIG Architecture as a new subproject. Similar to [Kubernetes Conformance Subproject.](https://github.com/kubernetes/community/blob/master/sig-architecture/README.md#conformance-definition-1 )

This aims to maintain and continue the [AI Conformance](https://github.com/cncf/k8s-ai-conformance) program in [Kubernetes](https://github.com/kubernetes-sigs/wg-ai-conformance).

Proposed Subproject Leads would be:

Janet Kuo ([@janetkuo](https://github.com/janetkuo)), Google
Mario Fahlandt ([@mfahlandt](https://github.com/mfahlandt)), Kubermatic GmbH
Rita Zhang ([@ritazh](https://github.com/ritazh)), Microsoft
Yuan Tang ([@terrytangyuan](https://github.com/terrytangyuan)), Red Hat

Slack Channel would be renamed to Slack: [#wg-ai-conformance](https://kubernetes.slack.com/messages/ai-conformance)

Start with sig-architecture/README.md and the linked AI Conformance and Kubernetes project pages. Review the proposed subproject leads and Slack-channel rename, then follow the SIG process for approving and recording the transition; done means the new subproject and its communication details are represented consistently.

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