CONTRIBUTING.md: link back to governance and include manifesto

CONTRIBUTING.md

@@ -2,3 +2,15 @@
 
 We're thrilled that you're interested in contributing to kcp! Please visit our
 [full contributing guide](https://docs.kcp.io/kcp/main/en/CONTRIBUTING/) on our documentation site.
+
+Beside that, what coverns the project and all contributions to it must follow
+the [KCP Project Governance](./GOVERNANCE.md).
+
+From the KCP Project GOVERNANCE, the following manifesto should guide the technical
+decisions through-out all contributions:
+
+> kcp maintainers strive to be good citizens in the Kubernetes project.
+> kcp maintainers see kcp always as part of the Kubernetes ecosystem and always strive to keep that ecosystem united. In particular, this means:
+> - kcp strives to not divert from Kubernetes, but strives to extend its use-cases to non-container control planes while keeping the ecosystems of libraries and tooling united.
+> - kcp – as a consumer of Kubernetes API Machinery – will strive to stay 100% compatible with the semantics of Kubernetes APIs, while removing container orchestration specific functionality.
+> - kcp strives to upstream changes to Kubernetes code as much as possible.