[doc] Issue in "Custom folder" for telco cloud

[e-minguez]

https://documentation.suse.com/suse-edge/3.4/html/edge/atip-management-cluster.html#mgmt-cluster-custom-folder

We should switch to use rancher turtles helm chart instead of disabling the webhooks and the capi feature via scripting.

[e-minguez]

Same for https://github.com/suse-edge/telco-cloud-examples/blob/main/telco-examples/mgmt-cluster/multi-node/eib/custom/files/metal3.sh#L69-L84