Site: Keep documentation and downloads information at a reasonable size

[snazy]

Is your feature request related to a problem? Please describe.

The (current state of) https://polaris.apache.org/ web site has a couple of Polaris release related pieces of information:

• Versioned docs
  • documentation per release version
  • documentation of the latest state on the main branch
  • accessible via the "Documentation" drop-down nav-bar menu
• Releases (downloads) page, containing
  • Links to release artifacts
  • Changelog for the release
• Search
  • All pages, including the docs for old releases, are indexed for the search functionality

There are some elements that could or even should be improved.

• Search: There are a couple of options to limit the amount of search results:
  • Exclude all but the in-dev and latest release from the search index
  • Exclude all but the in-dev and ["active" releases]((

    polaris/site/hugo.yaml

    Line 66 in 74c5835

    active_releases:

    )
• Releases (downloads) page.
  • Split the single page, as also proposed here
  • Either:
    • Have a separate page showing releases. Maybe split into active and older releases.
    • Move the individual download/changelog information to the versioned docs
• "Documentation" drop-down menu
  • Should it list all ever released versions?
  • Should it list all ["active" releases]((

    polaris/site/hugo.yaml

    Line 66 in 74c5835

    active_releases:

    )
  • In either "yes" for the above: a separate page showing the links for the "older" releases would be nice.

Ideally, a job that's part of the automated-release-workflow should help by creating PRs do perform changes against the web site content and config on the main branch.
Some changes, depending on the outcome(s) of the above bullet-list options, like adding a front-matter option to exclude pages from the search index, affect a lot of files.

Describe the solution you'd like

No response

Describe alternatives you've considered

No response

Additional context

No response