document the latest config under the kubeadm-init website page

[neolit123]

document the latest config we have here:
https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-init/

as discussed on the meeting:
https://docs.google.com/document/d/130_kiXjG7graFNSnIAgtMS1G8zPDwpkshgfRYS0nggo/edit#

kubeadm config: including godocs links vs inlining static configs vs generating configs in the future: #842
[Lubomir] What should we do with configs? link out? generate them? Current idea is to encode current version (v1alpha2) and link to the godoc.
[Tim] We should have a separate page that links out to all the detail of the config object. Mirroring content is bad. If docs link to godoc, then it forces devs to make sure the docs are up to date.
[Jennifer] We should branch for now. But relying on godocs is completely different than how the rest of the docs website works. Could bring it up to sig-docs. Make a proposal and present to sig-docs if we want to change how we reference code.
[Action Item] Generate data into docs and figure out a long term solution later.
[Tim] There has to be a deprecation policy on the old config

summary:
we can't do more for 1.11 other than including the latest output from kubeadm config print-default, mentioning the command and linking to godocs where we have comments for the fields.

@timothysc @Bradamant3

[neolit123]

this was merged:
kubernetes/website#8958