[enterprise-4.12] Issue in file scalability_and_performance/ztp_far_edge/ztp-reference-cluster-configuration-for-vdu.adoc

The 4.12 far-edge recommended configuration is missing one of the install-time manifests which should be included.

This section: https://docs.openshift.com/container-platform/4.14/scalability_and_performance/ztp_far_edge/ztp-reference-cluster-configuration-for-vdu.html#ztp-sno-install-time-cluster-config

Should include this CR as well:

https://github.com/openshift-kni/cnf-features-deploy/blob/release-4.12/ztp/source-crs/extra-manifest/05-kdump-config-master.yaml

The content is already in the 4.13+ versions.