Block web crawlers on v0.7-branch

[thesuperzapper]

Google keeps surfacing links from very old versions of the Kubeflow docs website, which is confusing to users.

This PR adds the <meta name="robots" content="noindex"> meta tag to tell Google to stop indexing the pages from the v0.7-branch branch.

It will take probably a few months (or longer) for Google to re-index these pages, I have left nofollow off, so that google will re-index the whole site quicker by following links.

---

It also backports the changes from #3863 so the version selector is consistent across each archive version.

And updates the OWNERS file of this very old branch to align with the current OWNERS in master to make it easier to approve PRs in the future without GitHub admin overrides.

[thesuperzapper]

The build is actually succeeding on this one, it's just that there is a random other Netlify build which is failing.

The only one that matters is the main one, so this can be merged.

[james-jwu]

/lgtm
/approve

[google-oss-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: james-jwu
Once this PR has been reviewed and has the lgtm label, please assign gaoning777 for approval. For more information see the Kubernetes Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[ederign]

/lgtm

[google-oss-prow]

New changes are detected. LGTM label has been removed.