ISSUE-16938: PIP-190-Part2: Modify the Versions page

[sijie]

Original Issue: apache#16938

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Is your feature request related to a problem? Please describe.
Refer to PIP-190.

Describe the solution you'd like
As part of PIP-190 implementation, we will narrow the listing of doc versions by modifying the versions.json file. Correspondingly, it brings changes to the last column of release notes, which is auto-generated by scripts.

Considering the main purpose of the Versions page and we already offer a summary page of release notes, we can modify the Versions page as follows.

1. remove the last column of specific release notes.
2. add a sentence to navigate users to the Release notes page.

cc @urfreespace