Migrate Reports API from Policy WG to OpenReports

[jvanz]

The goal of this issue is to migrate the API definition from the Kubernetes working group to a repository in this organization. This should include some of the following tasks:

• Create the repository to store the API. https://github.com/openreports/reports-api
• Move reports API from https://github.com/kubernetes-sigs/wg-policy-prototypes/tree/master/policy-report
• Rename from types PolicyReport to Report
• Move the content of the falco-adapter directory to the new repository
• Move the content of the kube-bench-adapter directory to the new repository
• Move the content of the kubearmor-adapter directory to the new repository
• Move the content of the oscal-transformer directory to the new repository
• Move the content of the trivy-adapter directory to the new repository.