Create separate Go module for test extension

This commit introduces dependency isolation by creating a separate
Go module for the OpenShift API Server test extension at
test/extended/tests-extension/.

Key benefits:
- Isolates test dependencies (ginkgo, gomega, openshift-tests-extension)
  from production operator code
- Prevents dependency version conflicts between operator and test framework
- Keeps production go.mod clean and focused on operator requirements
- Follows the pattern used by other OpenShift operators

The separate module includes:
- go.mod with test-specific dependencies
- go.sum with locked dependency versions
- Same k8s.io version pinning as root module via replace directives

Reference implementation:
https://github.com/openshift/operator-framework-operator-controller/tree/main/openshift/tests-extension

Author: gangwgr

test/extended/tests-extension/go.mod

@@ -0,0 +1,115 @@
+module github.com/openshift/openshift-apiserver/test/extended/tests-extension
+
+go 1.24.0
+
+require (
+	github.com/onsi/ginkgo/v2 v2.23.4
+	github.com/onsi/gomega v1.38.0
+	github.com/openshift-eng/openshift-tests-extension v0.0.0-20250804142706-7b3ab438a292
+	github.com/openshift/client-go v0.0.0-20250811163556-6193816ae379
+	k8s.io/api v0.33.3
+	k8s.io/apimachinery v0.33.3
+	k8s.io/client-go v0.33.3
+	k8s.io/kubectl v0.33.3
+	k8s.io/kubernetes v1.33.3
+)
+
+require (
+	cel.dev/expr v0.19.1 // indirect
+	github.com/antlr4-go/antlr/v4 v4.13.0 // indirect
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/blang/semver/v4 v4.0.0 // indirect
+	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
+	github.com/emicklei/go-restful/v3 v3.11.0 // indirect
+	github.com/fxamacker/cbor/v2 v2.7.0 // indirect
+	github.com/go-logr/logr v1.4.2 // indirect
+	github.com/go-openapi/jsonpointer v0.21.0 // indirect
+	github.com/go-openapi/jsonreference v0.20.2 // indirect
+	github.com/go-openapi/swag v0.23.0 // indirect
+	github.com/go-task/slim-sprig/v3 v3.0.0 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/google/cel-go v0.23.2 // indirect
+	github.com/google/gnostic-models v0.6.9 // indirect
+	github.com/google/go-cmp v0.7.0 // indirect
+	github.com/google/pprof v0.0.0-20250403155104-27863c87afa6 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	github.com/gorilla/websocket v1.5.4-0.20250319132907-e064f32e3674 // indirect
+	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
+	github.com/moby/spdystream v0.5.0 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
+	github.com/mxk/go-flowrate v0.0.0-20140419014527-cca7078d478f // indirect
+	github.com/openshift/api v0.0.0-20250820105013-6282350d0c39 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/prometheus/client_golang v1.22.0 // indirect
+	github.com/prometheus/client_model v0.6.1 // indirect
+	github.com/prometheus/common v0.62.0 // indirect
+	github.com/prometheus/procfs v0.15.1 // indirect
+	github.com/spf13/cobra v1.8.1 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/stoewer/go-strcase v1.3.0 // indirect
+	github.com/x448/float16 v0.8.4 // indirect
+	go.opentelemetry.io/otel v1.33.0 // indirect
+	go.opentelemetry.io/otel/trace v1.33.0 // indirect
+	golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56 // indirect
+	golang.org/x/net v0.41.0 // indirect
+	golang.org/x/oauth2 v0.27.0 // indirect
+	golang.org/x/sys v0.33.0 // indirect
+	golang.org/x/term v0.32.0 // indirect
+	golang.org/x/text v0.26.0 // indirect
+	golang.org/x/time v0.9.0 // indirect
+	golang.org/x/tools v0.33.0 // indirect
+	google.golang.org/genproto/googleapis/api v0.0.0-20241209162323-e6fa225c2576 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20241209162323-e6fa225c2576 // indirect
+	google.golang.org/protobuf v1.36.6 // indirect
+	gopkg.in/evanphx/json-patch.v4 v4.12.0 // indirect
+	gopkg.in/inf.v0 v0.9.1 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+	k8s.io/apiserver v0.33.3 // indirect
+	k8s.io/component-base v0.33.3 // indirect
+	k8s.io/klog/v2 v2.130.1 // indirect
+	k8s.io/kube-openapi v0.0.0-20250318190949-c8a335a9a2ff // indirect
+	k8s.io/pod-security-admission v0.0.0 // indirect
+	k8s.io/utils v0.0.0-20241210054802-24370beab758 // indirect
+	sigs.k8s.io/json v0.0.0-20241014173422-cfa47c3a1cc8 // indirect
+	sigs.k8s.io/randfill v1.0.0 // indirect
+	sigs.k8s.io/structured-merge-diff/v4 v4.6.0 // indirect
+	sigs.k8s.io/yaml v1.4.0 // indirect
+)
+
+replace (
+	github.com/onsi/ginkgo/v2 => github.com/openshift/onsi-ginkgo/v2 v2.6.1-0.20241205171354-8006f302fd12
+	k8s.io/api => k8s.io/api v0.33.3
+	k8s.io/apiextensions-apiserver => k8s.io/apiextensions-apiserver v0.33.3
+	k8s.io/apimachinery => k8s.io/apimachinery v0.33.3
+	k8s.io/apiserver => github.com/openshift/kubernetes-apiserver v0.0.0-20250917144435-182485d204aa
+	k8s.io/cli-runtime => k8s.io/cli-runtime v0.33.3
+	k8s.io/client-go => k8s.io/client-go v0.33.3
+	k8s.io/cloud-provider => k8s.io/cloud-provider v0.33.3
+	k8s.io/cluster-bootstrap => k8s.io/cluster-bootstrap v0.33.3
+	k8s.io/code-generator => k8s.io/code-generator v0.33.3
+	k8s.io/component-base => k8s.io/component-base v0.33.3
+	k8s.io/component-helpers => k8s.io/component-helpers v0.33.3
+	k8s.io/controller-manager => k8s.io/controller-manager v0.33.3
+	k8s.io/cri-api => k8s.io/cri-api v0.33.3
+	k8s.io/csi-translation-lib => k8s.io/csi-translation-lib v0.33.3
+	k8s.io/dynamic-resource-allocation => k8s.io/dynamic-resource-allocation v0.33.3
+	k8s.io/endpointslice => k8s.io/endpointslice v0.33.3
+	k8s.io/kms => k8s.io/kms v0.33.3
+	k8s.io/kube-aggregator => k8s.io/kube-aggregator v0.33.3
+	k8s.io/kube-controller-manager => k8s.io/kube-controller-manager v0.33.3
+	k8s.io/kube-proxy => k8s.io/kube-proxy v0.33.3
+	k8s.io/kube-scheduler => k8s.io/kube-scheduler v0.33.3
+	k8s.io/kubectl => k8s.io/kubectl v0.33.3
+	k8s.io/kubelet => k8s.io/kubelet v0.33.3
+	k8s.io/legacy-cloud-providers => k8s.io/legacy-cloud-providers v0.33.3
+	k8s.io/metrics => k8s.io/metrics v0.33.3
+	k8s.io/mount-utils => k8s.io/mount-utils v0.33.3
+	k8s.io/pod-security-admission => k8s.io/pod-security-admission v0.33.3
+	k8s.io/sample-apiserver => k8s.io/sample-apiserver v0.33.3
+)