Remove openshift-sdn-based CI jobs by 4.17 (ironic)

openshift-sdn is no longer supported for new installs as of 4.15, and it will be completely removed from OpenShift in 4.17.

Your component currently has one or more CI jobs that use openshift-sdn:

ci-operator/config/openshift/ironic-agent-image/openshift-ironic-agent-image-main__prevalidation.yaml
  e2e-metal-ipi-bm-prevalidation
  e2e-metal-ipi-serial-ipv4-prevalidation

ci-operator/config/openshift/ironic-agent-image/openshift-ironic-agent-image-main.yaml
  e2e-metal-ipi-bm
  e2e-metal-ipi-serial-ipv4

ci-operator/config/openshift/ironic-hardware-inventory-recorder-image/openshift-ironic-hardware-inventory-recorder-image-master.yaml
  e2e-metal-ipi

ci-operator/config/openshift/ironic-image/openshift-ironic-image-master__prevalidation.yaml
  e2e-metal-ipi-bm-prevalidation

ci-operator/config/openshift/ironic-image/openshift-ironic-image-master.yaml
  e2e-metal-ipi-bm

ci-operator/config/openshift/ironic-ipa-downloader/openshift-ironic-ipa-downloader-master.yaml
  e2e-metal-ipi-bm

ci-operator/config/openshift/ironic-rhcos-downloader/openshift-ironic-rhcos-downloader-master.yaml
  e2e-metal-ipi
  e2e-metal-ipi-serial-ipv4

ci-operator/config/openshift/ironic-static-ip-manager/openshift-ironic-static-ip-manager-master.yaml
  e2e-metal-ipi-bm
  e2e-metal-ipi-serial-ipv4
  e2e-metal-ipi-upgrade

These jobs will need to be removed or migrated to ovn-kubernetes by OCP 4.17. In some cases, if you were not intentionally testing openshift-sdn, it may make sense to start migrating these jobs in 4.15. You may want to split this bug into multiple bugs for different OCP versions.

Component-specific notes:

• Many of these repos use the common pattern of testing baremetal with sdn+ipv4 and ovn+ipv6. Depending on your testing needs, it may make sense to remove the sdn+ipv4 jobs and keep just the ovn+ipv6 ones, or to replace the sdn+ipv4 jobs with ovn+ipv4, or to replace both jobs with a single ovn+ipv4 job.
• Previously, there was no workflow for running the serial or upgrade test suites on bare metal with ovn-kubernetes and IPv4, so some components run it with openshift-sdn and IPv4, and other components run it with ovn-kubernetes and IPv6, and others do both. There are now baremetalds-e2e-serial-ovn-ipv4 and baremetalds-e2e-upgrade-ovn-ipv4 workflows if you want to change any of the sdn+ipv4 (or ovn+ipv6) jobs to ovn+ipv4.