NE-2215: add CI step and presubmits for testing HAProxy 2.8

Add CI jobs for testing the non-default HAProxy version (2.8)
with the IngressControllerMultipleHAProxyVersions TechPreview feature gate:

- ingress-conf-haproxy-version step: writes an IngressController manifest
  to SHARED_DIR with the specified haproxyVersion, run before ipi-install

cluster-ingress-operator presubmits:
- e2e-aws-ovn-haproxy28-techpreview: optional conformance presubmit
- e2e-aws-operator-haproxy28-techpreview: optional CIO e2e presubmit
- e2e-aws-ovn-upgrade-haproxy28-techpreview: optional upgrade presubmit
- e2e-aws-ovn-serial-haproxy28-techpreview: optional serial presubmit (2 shards)

router presubmits:
- e2e-agnostic-haproxy28-techpreview: optional conformance presubmit (GCP)
- e2e-aws-serial-haproxy28-techpreview: optional serial presubmit (2 shards)
- e2e-aws-ovn-upgrade-haproxy28-techpreview: optional upgrade presubmit

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: gcs278

ci-operator/config/openshift/cluster-ingress-operator/openshift-cluster-ingress-operator-master.yaml

@@ -153,12 +153,39 @@ tests:
   steps:
     cluster_profile: openshift-org-aws
     workflow: openshift-upgrade-aws
+- always_run: false
+  as: e2e-aws-ovn-upgrade-haproxy28-techpreview
+  optional: true
+  steps:
+    cluster_profile: openshift-org-aws
+    env:
+      FEATURE_SET: TechPreviewNoUpgrade
+      HAPROXY_VERSION: "2.8"
+    pre:
+    - chain: ipi-conf-aws
+    - ref: ingress-conf-haproxy-version
+    - chain: ipi-install
+    workflow: openshift-upgrade-aws
 - as: e2e-aws-ovn-serial
   shard_count: 2
   skip_if_only_changed: ^docs/|\.md$|^(?:.*/)?(?:\.gitignore|OWNERS|OWNERS_ALIASES|PROJECT|LICENSE)$
   steps:
     cluster_profile: openshift-org-aws
     workflow: openshift-e2e-aws-serial
+- always_run: false
+  as: e2e-aws-ovn-serial-haproxy28-techpreview
+  optional: true
+  shard_count: 2
+  steps:
+    cluster_profile: openshift-org-aws
+    env:
+      FEATURE_SET: TechPreviewNoUpgrade
+      HAPROXY_VERSION: "2.8"
+    pre:
+    - chain: ipi-conf-aws
+    - ref: ingress-conf-haproxy-version
+    - chain: ipi-install
+    workflow: openshift-e2e-aws-serial
 - always_run: false
   as: e2e-aws-ovn-single-node
   optional: true
@@ -279,6 +306,19 @@ tests:
     env:
       FEATURE_SET: TechPreviewNoUpgrade
     workflow: openshift-e2e-aws
+- always_run: false
+  as: e2e-aws-ovn-haproxy28-techpreview
+  optional: true
+  steps:
+    cluster_profile: openshift-org-aws
+    env:
+      FEATURE_SET: TechPreviewNoUpgrade
+      HAPROXY_VERSION: "2.8"
+    pre:
+    - chain: ipi-conf-aws
+    - ref: ingress-conf-haproxy-version
+    - chain: ipi-install
+    workflow: openshift-e2e-aws
 - always_run: false
   as: e2e-ibmcloud-operator
   optional: true
@@ -309,6 +349,27 @@ tests:
         requests:
           cpu: 100m
     workflow: ipi-aws
+- always_run: false
+  as: e2e-aws-operator-haproxy28-techpreview
+  optional: true
+  steps:
+    cluster_profile: openshift-org-aws
+    env:
+      FEATURE_SET: TechPreviewNoUpgrade
+      HAPROXY_VERSION: "2.8"
+    pre:
+    - chain: ipi-conf-aws
+    - ref: ingress-conf-haproxy-version
+    - chain: ipi-install
+    test:
+    - as: test
+      cli: latest
+      commands: make test-e2e
+      from: src
+      resources:
+        requests:
+          cpu: 100m
+    workflow: ipi-aws
 - always_run: false
   as: e2e-openstack-operator
   optional: true

ci-operator/config/openshift/router/openshift-router-master.yaml

@@ -115,6 +115,50 @@ tests:
   steps:
     cluster_profile: openshift-org-aws
     workflow: openshift-e2e-aws-serial
+- always_run: false
+  as: e2e-aws-serial-haproxy28-techpreview
+  optional: true
+  shard_count: 2
+  steps:
+    cluster_profile: openshift-org-aws
+    env:
+      FEATURE_SET: TechPreviewNoUpgrade
+      HAPROXY_VERSION: "2.8"
+    pre:
+    - chain: ipi-conf-aws
+    - ref: ingress-conf-haproxy-version
+    - chain: ipi-install
+    workflow: openshift-e2e-aws-serial
+- always_run: false
+  as: e2e-agnostic-haproxy28-techpreview
+  optional: true
+  steps:
+    cluster_profile: openshift-org-gcp
+    env:
+      FEATURE_SET: TechPreviewNoUpgrade
+      HAPROXY_VERSION: "2.8"
+    post:
+    - chain: gather-core-dump
+    - chain: ipi-gcp-post
+    pre:
+    - ref: enable-node-coredumps
+    - chain: ipi-conf-gcp
+    - ref: ingress-conf-haproxy-version
+    - chain: ipi-install
+    workflow: openshift-e2e-gcp
+- always_run: false
+  as: e2e-aws-ovn-upgrade-haproxy28-techpreview
+  optional: true
+  steps:
+    cluster_profile: openshift-org-aws
+    env:
+      FEATURE_SET: TechPreviewNoUpgrade
+      HAPROXY_VERSION: "2.8"
+    pre:
+    - chain: ipi-conf-aws
+    - ref: ingress-conf-haproxy-version
+    - chain: ipi-install
+    workflow: openshift-upgrade-aws
 - always_run: false
   as: e2e-metal-ipi-ovn-router
   capabilities: