chore: update to oci references (#615)

Author: xeniape

tests/templates/kuttl/opa/40-install-test-container.yaml.j2

@@ -55,7 +55,7 @@ spec:
         fsGroup: 1000
       containers:
         - name: test-runner
-          image: docker.stackable.tech/stackable/testing-tools:0.2.0-stackable0.0.0-dev
+          image: oci.stackable.tech/sdp/testing-tools:0.2.0-stackable0.0.0-dev
           stdin: true
           tty: true
           resources: