Migrate to `clusterpolicyreports.x-k8s.io` `v1beta2`

[viccuad]

The published PolicyReports CRDs are moving from clusterpolicyreports.wgpolicyk8s.io to clusterpolicyreports.x-k8s.io. In addition, the already existing v1beta2 is now actually instead of v1alpha2. See here.

Historically, the CRDs never had a proper release, and we were consuming them from the repository tree.

This seems also in flux at time of writing.

Acceptance criteria

• [ ] Make sure v1beta2 is consumable (see other community consumers).
• [ ] Make sure we depend on the same PolicyReport CRDs as policy-reporter.
• [ ] Bump the CRDs GVK on audit-scanner.
• [ ] Bump the CRDs on the E2E tests.
  • Make sure that Helm chart upgrades are possible.
• [ ] Make sure the Kubewarden UI expects the correct PolicyReport CRD.
• [ ] Update docs.kubewarden.io as needed.
• [ ] Make sure that upgrade.