[RFE] Enhance rancher2_cluster_v2.cluster_registration_token to return the insecure node command for registering downstream linux custom cluster nodes

[Josh-Diamond]

Is your feature request related to a problem? Please describe.

Currently, only the node command is available with the cluster_registration_token attribute on the rancher2_cluster_v2 resource. This request is to also accommodate the Insecure Node command to execute in Linux nodes for custom k8s clusters

Describe the solution you'd like

Add support for the Insecure Node command to be executed in registering Linux nodes for custom k8s clusters

Additional context

Insecure node command is available for importing k8s clusters, just not for registering custom nodes.

Screenshot:

https://registry.terraform.io/providers/rancher/rancher2/latest/docs/resources/cluster_v2