Migrate openshift assisted installer version to ocm-2.12

What does this MR do and why?

This is to follow up sylva-projects/sylva-elements/helm-charts/sylva-capi-cluster!424 (comment 2171333496)

OpenShift assisted installer ocm-2.12 branch latest image support mac-address identifier NMState line, with this update, these lines can be accepted by the openshift assisted installer,

 identifier: mac-address
 mac-address: 00:60:2f:31:81:03

Once this MR is merged, we can remove the cabpoa case described in sylva-projects/sylva-elements/helm-charts/sylva-capi-cluster!424 (comment 2171333496)

The kustomization resource git url timeout is changed from default to 300s, as occasionally we noticed a git url timeout described here: https://github.com/kubernetes-sigs/kustomize/issues/3742