Deprecate 1.9 documentation

[rimolive]

With Kubeflow 1.10 released, we will deprecate 1.9 documentation.

cc @thesuperzapper

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[thesuperzapper]

We actually also need to move template updates I was proposing in #3862, not just set archived to true.

We should also merge an updated version of #3863 which will add the updated templates to master so we only have to set the flag in future. (We will also need to chery pick this into the 1.10 branch so that one is easy to archive when the time comes).